题目内容：

1.with his attention ( ) on the job ,he did noteven look up when we came in
A focused B focusing C to focus D having focused
为什么选A 不选B
2.The lady ( ) thirty poor students go to college by the end of last year.
A helped B had helped C has helped Dwould have helped
为什么选B不选C
分析分析.
3.( )all of the questions have been settled ,you can go on with your work
A only if (除非..才) B even though (即使) C now that (既然,由于) D what if(倘使...将会怎样;即使...又有什么要紧)
我查了意思.为什么选C不选A