The clever boy made a hole in the wall, ____ he could see ____ was going on inside the house.
_________ I felt somewhat disappointed and was about to leave,something occurred which attracted my attention.
There is no doubt that he is a good professor__________he is doing fine.
__________ there are a large number of chemical factories,the air is likely to be polluted.
_________,this kind of disease can do great harm to people there.
I’m willing to lend you a hand__________busy I’m for the moment.