第1个回答 2011-10-31
I cannot join you, as I have so much homework to do.本回答被提问者采纳
第2个回答 2011-10-31
I couldn't join you,I have too much homework to do.
第3个回答 2011-10-31
I have too much work to do to join you.
I can't join you because I have a lot of work to do