Over the past decades, sea ice _______ in the Arctic as a result of global warming. [ ]
The question is very difficult and of the students can answer it.
Food supplies in the flood-stricken area______.We must act immediately before there’s left. [ ]
Which do you like, the former or the ___.
Someone is knocking at the door, who _____ it be?It _____ be Danny. He’s in hospital for some time. [ ]