1.Isn't it time you got down to ----- the papers?
A。mark B.marking
2.----with so much trouble,we failed to complete the task on time.
A.Faced B.Facing
3.----for the breakdown of the school computer network,Alice was in low spirits.
A.Blamed B.To blame
4.AIDS is said ----the biggest health challenge over the past few years.
A. that it has been B.to have been
有答案，要解析！！坐等!!
补充几道！坐等！
1.When and wher he came here (is/has)not known yet.
2.They discussed (if/whether)they could settle the problem without his help.
3.He insisted that he was in good health and (is /be) sent to work there.
第1题和第3题 我原来选的答案和你一样，但是参考书的答案是另外的一个。你确定你对了吗
追答get down to doing,这里的to,介词，不是不定式，
被责怪那题，我想没什么问题
麻烦再帮几道
追答恩
不是 我知道意思
结构问题
分析一下
答案？
追问我去、意思都不对，离谱啊！！你用什么翻译的....
比如，AIDS是艾滋病的意思。。
求解，坐等各位高手！！
1A,to do sth,get down to do sth,定下心来做某事
2，A,非谓语考点，（有逗号，没连词），是这个状语从句的改写：
because we were faced with so much trouble,we failed to complete the task on time.
从句找被省略的主语，we,然后找we 和face的关系，是被动关系，用过去分词，没有with的话，用现在分词
3.A,解题思路同上，省略的主语是ALICE,如用to do,表将来，为了责备，逻辑不通
4，B从over the past few years.知道事态是完成时，不定式的完成时
A,要这么表达：
It is said that aids has been the biggest health challenge 。。。
要么是It is said that
要么是sth is said to be
我不要抄别人的答案
第二题错了，呵呵
sb. be faced with