It is necessary that the students ____ more excercises to do.
A、haveA
【句意】学生们有必要做更多的练习。
【难点】虚拟语气可以用于主语从句中，常用的句型为：It+is(was)+形容词that…，主语从句中的谓语用(should)+v.的表达形式。
The____ofAIDShasledtoanexpansioninresearchseekingacure.
______hardworkitis!
Tom____ofhiswifehowshehadmetherfriend.
Physicsisthepresentdayequivalentof____usedtobecallednaturalphilosophy,from____mostofpresentdaysciencearose.
As____clearfromhismanners,heisateacher.
