第6課
關(guān)于逗號的一些知識
原則：逗號沒有能力連接兩個單獨的句子。
如何區(qū)分短語與句子？一個結(jié)構(gòu)如果有完整的謂語部分就是句子。
何為完整的謂語部分？如果能判斷出一個結(jié)構(gòu)的時態(tài)就可以稱這個結(jié)構(gòu)為完整的謂語部分。
在什么樣的情況下一個逗號可以將句子分成兩部分，而這兩部分都有完整的謂語呢？
1 兩個句子中間有連接詞連接；
2 這兩個句子是主從句關(guān)系（主從句之間一定要有句子引導(dǎo)詞來引導(dǎo)）。
10. Walter offered us a lift when he wasleaving the office, but our work _A_, we declined the offer. [declined v. 婉言謝絕]
A not being finished B not having finished
C had not been finished D was not finished
42. A survey was carrie3d out on the deathrate of new-born babies in that region, _D_ were surprising. [survey 調(diào)查]
A as results B which results C the results of it D the results of which
51. All flights _D_ because of thesnowstorm, many passengers could no nothing but take the train. [having beencanceled這里是獨立主格作原因狀語]
A had been canceled B have been canceled
C were canceled D having been canceled