Questions 31 to 36 are based on the following passage：
The focusing or sharpening of the image is performed by a special apparatus.In every camera，the farther the object is from the eye，the farther forward—and the nearer the object is to the eye，the farther backward—is its image thrown.In photographers'cameras，the back is made to slide，and can be drawn away from the lens when the object that casts the picture near， and pushed forward when it is far.The picture is thus kept always sharp.But no such change of length is possible in the eyeball，and the same result is reached in another way.The lens， namely，grows more convex（凸面的）when a near object is looked at，and flatter when the object recedes.This change is due to the antagonism of the“ciliary muscle（睫狀肌）。The ligament（韌帶），when the ciliary muscle is at rest，assumes such a spreadout shape as to keep the lens rather flat.But the lens is highly elastic；and it springs into the more convex form which is natural to it whenever the ciliary muscle，by contracting， makes the ligament relax its pressure.The contraction of the muscle，by thus tendering the lens more refractive，adapts the eye for near objects（”accommodatesit for them，as we say）：and its relaxation，by rendering the lens less refractive， adapts the eye for distant vision.Accommodation for the near is thus the more active change，since it involves contraction of the ciliary muscle.When we look far off，we simply let our eyes go passive. We feel the difference in the effort when we compare the two sensation of change.
31.In order to focus on distant objects，the lens of the eye ____ .
A）becomes more convex B）becomes more active
C）becomes more refractive D）flattens
32.The ligament，when not acted on by the contraction of the ciliary muscle，____ .
A）maintains its pressure on the lens so that the lens remains flat
B）relaxes its pressure on the lens so that it remains convex
C）maintains its pressure on the lens so that the lens remains convex
D）relaxes its pressure on the lens so that it remains flat
33.Functionally，we may compare ____ .
A）the lens of the camera with the lens of the eye
B）the lens of the camera with the ciliary muscle
C）the lens of the eye with the sliding of the back of the camera
D）the sliding of the back of the camera with the adaptability of the eyeball
34.Which of the following activities is most tiring for the lens of the eye？
A）Looking at a distant mountain.
B）Being a“sidewalk superintendent。
C）Watching squirrels being fed.
D）Reading a book.
35.The tone of this passage can best be described as ____ .
A）professionally scientific B）argumentative
C）matter of fact and formal D）informal and matter of fact
Questions 36 to 40 are based on the following passage：
Are you aware that you actually possess six senses？The sixth is a muscular sense responsible for directing your muscles intelligently to the exact extent necessary for each action you perform.For example，when you reach for an object，the sensory nerves linking the muscles to the brain stop your hand at the correct spot.This automatic perception of the position of your muscles in relation to the object is your muscular sense in action.
The focusing or sharpening of the image is performed by a special apparatus.In every camera，the farther the object is from the eye，the farther forward—and the nearer the object is to the eye，the farther backward—is its image thrown.In photographers'cameras，the back is made to slide，and can be drawn away from the lens when the object that casts the picture near， and pushed forward when it is far.The picture is thus kept always sharp.But no such change of length is possible in the eyeball，and the same result is reached in another way.The lens， namely，grows more convex（凸面的）when a near object is looked at，and flatter when the object recedes.This change is due to the antagonism of the“ciliary muscle（睫狀肌）。The ligament（韌帶），when the ciliary muscle is at rest，assumes such a spreadout shape as to keep the lens rather flat.But the lens is highly elastic；and it springs into the more convex form which is natural to it whenever the ciliary muscle，by contracting， makes the ligament relax its pressure.The contraction of the muscle，by thus tendering the lens more refractive，adapts the eye for near objects（”accommodatesit for them，as we say）：and its relaxation，by rendering the lens less refractive， adapts the eye for distant vision.Accommodation for the near is thus the more active change，since it involves contraction of the ciliary muscle.When we look far off，we simply let our eyes go passive. We feel the difference in the effort when we compare the two sensation of change.
31.In order to focus on distant objects，the lens of the eye ____ .
A）becomes more convex B）becomes more active
C）becomes more refractive D）flattens
32.The ligament，when not acted on by the contraction of the ciliary muscle，____ .
A）maintains its pressure on the lens so that the lens remains flat
B）relaxes its pressure on the lens so that it remains convex
C）maintains its pressure on the lens so that the lens remains convex
D）relaxes its pressure on the lens so that it remains flat
33.Functionally，we may compare ____ .
A）the lens of the camera with the lens of the eye
B）the lens of the camera with the ciliary muscle
C）the lens of the eye with the sliding of the back of the camera
D）the sliding of the back of the camera with the adaptability of the eyeball
34.Which of the following activities is most tiring for the lens of the eye？
A）Looking at a distant mountain.
B）Being a“sidewalk superintendent。
C）Watching squirrels being fed.
D）Reading a book.
35.The tone of this passage can best be described as ____ .
A）professionally scientific B）argumentative
C）matter of fact and formal D）informal and matter of fact
Questions 36 to 40 are based on the following passage：
Are you aware that you actually possess six senses？The sixth is a muscular sense responsible for directing your muscles intelligently to the exact extent necessary for each action you perform.For example，when you reach for an object，the sensory nerves linking the muscles to the brain stop your hand at the correct spot.This automatic perception of the position of your muscles in relation to the object is your muscular sense in action.