以下各句均有一处错误,请找出,并在括号内改正
1. Can you tell me how can I learn English well? (can I--- I can 从句,正常语序 )
2.I haven't decided when to go for my summer holiday , maybe Hangzhou.(when--where)
3. I don't know if Tom will come or not.(if--whether因为有or not )
4.Do you know when will teach us English next term?( when---who)