Re: Four questions of Toefl's grammer test. Which one is correct?
M!do, this is not the way the forum works. You need to do two things:
1. Delete questions #2 to #4, and post them as separate threads. If different people respond to different questions in one thread, confusion often results. That is why forum policy is: one question per thread (with follow-up questions of course).
2. Make some attempt to give the response you think is correct. If you think two options could be correct, tell us. Your answers will help us to help you.
Please do not edit your question after it has received a response. Such editing can make the response hard for others to understand.