The task is too much for him, so he can’t continue ______any longer. He must get some help.

Tony can’t have received the invitation. ________, he would have attended your birthday party yesterday.

There were a lot of people standing at the door and the small girl couldn’t get _______      

.．As is often pointed out, knowledge is a two-edged weapon which can be used_____________for good or evil.

Because of the rise of sea level, some islands will disappear. _____ people of certain countries will have to look for new places to live.