18 判断表示原因、伴随、结果还是
表目的
①Lots of rescue workers were working around the clock, ______ supplies to Yushu, Qinghai Province after the earthquake.
A. sending B. to send
C. having sent D. to have sent
②I explained the theory as clearly as possible, ______ to make it easy ______. A. to hope; to understand B. hoped; understood C. hoping; to understand D. to hope; to be understood 【答案】①A ②C
19 there be 结构
there＋be＋名词＋doing/done/to do；
deny/appreciate/mind/imagine/admit＋介词＋there being；
want/expect/hope/wish/like/hate/would like/prefer/mean/intend＋there to be。 there being是独立主格结构。
There is no doing 意为“不可能……，无法……”。
用所给词的适当形式填空：
①There is a great deal of evidence ________(indicate) that music activities engage different parts of the brain.
②The students expected there ________(be) more reviewing classes before the final exams.
③Ann never dreams of there ________(be)for her to be sent abroad very soon. ④There ________(be) no money left, I can't buy the book. 【答案】①indicating ②to be ③being ④being
20 不定式to后的省略
一般保留动词不定式符号to，若to后有助动词have, be, have been, 则也要保留。
①The boy wanted to ride his bicycle in the street, but his mother told him ________．
A. not to B. not to do C. not do it D. do not to ②In my opinion, life in the twenty－first century is much easier than ________． A. that used to be B. it is used to C. it was used to D. it used to be
③—You should have worked harder. —I know I ________．
A. ought to B. ought to have
C. should D. will
④—He wasn't helped yesterday. —He ought to ________． A. have B. be
C. have been D. have done 【答案】①A ②D ③B ④C
21 不定式to的省略
①不定式作表语时，如果前面有实义动词do的形式时，to要省略； ②不定式作感官动词和使役动词的宾语补足语时，要省略to；
③由并列连词and，except, but, than, or 连接两个以上的具有相同意义或功能的不定式时，第二个动词不定式不带to；
[注]如果两个不定式表示对照或对比，则不能省略to。如： It's easier to make a plan than to carry it out.
④动词help后用作宾语或宾语补足语时，不定式可以不带to；
⑤“why not＋省略to的不定式(动词原形)”表示建议，意为“为什么不”； “why ＋省略to的不定式(动词原形)”表示不赞成； ⑥动词不定式作but, except的宾语时，如果前面有实义动词do的形式时，要省略to； ⑦不定式构成的特殊句式：
too 与ready, easy, willing, eager, anxious等形容词连用，此时不定式没有否定意义，too相当于very。如：
I am too willing to help you.
too在not, never, only, all, but后，不定式表示肯定含义。