一般时

进行时

完成时

完成进行时

现在

study
studies

am studying
is studying
are studying

have studied
has studied

have been studying
has been studying

过去

studied

was studying
were studying

had studied

had been studying

将来

shall study
will study

shall be studying
will be studying

shall have studied
will have studied

shall have been studying
will have been studying

过去将来

should study
would study

should be studying
would be studying

should have studied
would have studied

should have been studying
would have been studying

 

3) D错。本句主语是A desert area…will still bloom，状语从句是由when引导，表示“雨季到来时”，从句的谓语应用一般现在时表示将来，所以将C处的will come改为comes。

4) 正确答案为C。本题除了时态上的问题(即不用一般将来时)之外还涉及到主语和它的表语的逻辑问题。根据上述语法特点，首先排除B和D；题中“convenient”是“方便的”之意。虽然汉语“在你方便的时候”，似乎“方便”的主语是“你”，但在英语中就不是那么回事儿，“convenient”的英文的解释是“(sth) suited to personal ease or comfort or to easy performance of some act or function”(某事或物对某人来说感到舒适或容易作)，其主语应是“物”而不是“人”。本题应选C。所以学英语时，不仅要懂英语单词的汉语译文，更重要的是掌握英语单词的内涵与用法。建议身边备一个“英英”字典，如Longman Dictionary of Comtempory English。

5) C为正确答案。理由同上。