I can go with you because l haven't _____.A.do sth B.sth do

I can go with you because l haven't _____.A.do sth B.sth do I can't go hiking with you because I have a lot of () to do can you do sth. can't but do sth A：Hello.what can I do _____ you?B:Hello.I want to _____ a T- can't help do sth/can't help to do sth./can't help doing sth I have ___much homework to do that I can't go with you A.so i can't go with you tonight ( ) I have homework to do.A.befo Can you do sth还是Can you doing sth 如果说i can't do sth.如何回答? I can't go.Because I have so many things--a,done b,to do c.t go on to do sth ,go on doing sth,go on with sth有什么区别