I was ___ the point of telephoning him when his letter arrived.
The reason why I gave in is ____ if I didn’t.
No matter how fast we worked, ____.
The teacher found ____ difficult to decide ____ he would take with him to attend the conference.
Living things are dying out quickly. Let’s ask ____ destroying them in the past years.
The man who was being followed stopped from time to time ____ he wanted to tie his shoelaces.