一般人對(duì)英語里基本時(shí)態(tài)的意義和用法都沒有什么問題，但是未必每個(gè)人都對(duì)某些尋常時(shí)態(tài)的特殊用法有足夠的體會(huì)。
請(qǐng)看下面這三種情形：
Ⅰ 現(xiàn)在簡單時(shí)態(tài)
⒈現(xiàn)在簡單時(shí)態(tài)可以用來表示未來的動(dòng)作或活動(dòng)，但這活動(dòng)必須事先已有計(jì)劃，如：
● The plane to Hawaii leaves at 10 tonight.
● The British Prime Minister arrives at 8 tomorrow morning.
這樣的不尋常時(shí)態(tài)里的動(dòng)詞通常只限于“來”和“往”之類的活動(dòng)，不是任何動(dòng)詞都適用。
⒉現(xiàn)在簡單時(shí)態(tài)也可用來取代時(shí)間副詞分句（adverb clauses of time）或條件副詞分句（adverb clauses of condition）中的現(xiàn)在未來時(shí)態(tài)，如：
● Let's wait until all the guests come.
● If it rains tomorrow, we can't go fishing.
理論上可以說“until all the guests will come”和“if it will rain tomorrow”，但實(shí)際句子里，并不如此。
⒊現(xiàn)在簡單時(shí)態(tài)有時(shí)可以用來代替現(xiàn)在過去時(shí)態(tài)，使所敘述的事物更現(xiàn)實(shí)、更靈活，如：
● Alexander Pope says, “A little learning is a dangerous thing.”
● The Chinese proverb has it, “God helps those who help themselves.”
只有在特殊情況下，才用這種時(shí)態(tài)；否則，過去的事， 只好用過去時(shí)態(tài)，比較妥當(dāng)。
Ⅱ 現(xiàn)在進(jìn)行時(shí)態(tài)
⒈現(xiàn)在進(jìn)行時(shí)態(tài)可以用來表示未來的節(jié)目或已策劃的活動(dòng)，如：
● They are going downtown this afternoon.
● I am seeing an old friend tonight.
⒉現(xiàn)在進(jìn)行時(shí)態(tài)，也和副詞“always, continually, constantly”等連用以表示不斷重復(fù)的舉動(dòng)，言下有不勝其煩之感，如：
● Janet is always complaining.
● Why are you continually finding fault with our new system?
● Strange! The weather here is constantly changing.
Ⅲ 過去簡單時(shí)態(tài)
⒈過去簡單時(shí)態(tài)可用來表示目前不易實(shí)現(xiàn)的假設(shè)或愿望，如：
● lf I were you, I would join that activity.
● I wish I had better luck next time.
⒉過去簡單時(shí)態(tài)也可以用來代替現(xiàn)在簡單時(shí)態(tài)，以表示禮貌，如：
● Could you tell me how to go to the library?
● I would appreciate it if you could help me.
● Would you mind lending me your pen for a while?
上述尋常時(shí)態(tài)的不尋常用法，如果用得恰當(dāng)，肯定可以增添英語的靈活性。
請(qǐng)看下面這三種情形：
Ⅰ 現(xiàn)在簡單時(shí)態(tài)
⒈現(xiàn)在簡單時(shí)態(tài)可以用來表示未來的動(dòng)作或活動(dòng)，但這活動(dòng)必須事先已有計(jì)劃，如：
● The plane to Hawaii leaves at 10 tonight.
● The British Prime Minister arrives at 8 tomorrow morning.
這樣的不尋常時(shí)態(tài)里的動(dòng)詞通常只限于“來”和“往”之類的活動(dòng)，不是任何動(dòng)詞都適用。
⒉現(xiàn)在簡單時(shí)態(tài)也可用來取代時(shí)間副詞分句（adverb clauses of time）或條件副詞分句（adverb clauses of condition）中的現(xiàn)在未來時(shí)態(tài)，如：
● Let's wait until all the guests come.
● If it rains tomorrow, we can't go fishing.
理論上可以說“until all the guests will come”和“if it will rain tomorrow”，但實(shí)際句子里，并不如此。
⒊現(xiàn)在簡單時(shí)態(tài)有時(shí)可以用來代替現(xiàn)在過去時(shí)態(tài)，使所敘述的事物更現(xiàn)實(shí)、更靈活，如：
● Alexander Pope says, “A little learning is a dangerous thing.”
● The Chinese proverb has it, “God helps those who help themselves.”
只有在特殊情況下，才用這種時(shí)態(tài)；否則，過去的事， 只好用過去時(shí)態(tài)，比較妥當(dāng)。
Ⅱ 現(xiàn)在進(jìn)行時(shí)態(tài)
⒈現(xiàn)在進(jìn)行時(shí)態(tài)可以用來表示未來的節(jié)目或已策劃的活動(dòng)，如：
● They are going downtown this afternoon.
● I am seeing an old friend tonight.
⒉現(xiàn)在進(jìn)行時(shí)態(tài)，也和副詞“always, continually, constantly”等連用以表示不斷重復(fù)的舉動(dòng)，言下有不勝其煩之感，如：
● Janet is always complaining.
● Why are you continually finding fault with our new system?
● Strange! The weather here is constantly changing.
Ⅲ 過去簡單時(shí)態(tài)
⒈過去簡單時(shí)態(tài)可用來表示目前不易實(shí)現(xiàn)的假設(shè)或愿望，如：
● lf I were you, I would join that activity.
● I wish I had better luck next time.
⒉過去簡單時(shí)態(tài)也可以用來代替現(xiàn)在簡單時(shí)態(tài)，以表示禮貌，如：
● Could you tell me how to go to the library?
● I would appreciate it if you could help me.
● Would you mind lending me your pen for a while?
上述尋常時(shí)態(tài)的不尋常用法，如果用得恰當(dāng)，肯定可以增添英語的靈活性。