Charles did what he could _____ the servant, although he himself was in danger.
I can’t _____ his failure.It is unbelievable.
--- Who left the door open? --- Oh, sorry. I _____ the door.
.The traffic problems we are looking forward to ______ solved should have attracted the government’s attention.
.He seemed to be looking for the words ____ he could express his idea.
.A modern city has been set up in ____ was a wasteland ten years ago.