—Li Ming went abroad in 2000. —No wonder. I ______ him ever since.
It is uncertain ______ side effect the medicine will bring about, although about two thousand patients have taken it.
The English in the future will be quite different from the English of today. It is possible that some English words may even ________ completely.
Rainforests __________ and burned at such a speed that they will disappear from the earth in the near future.
_______ the rain falling so hard, it becomes more and more difficult to carry on the rescue work.
At a beach or a swimming pool a lifeguard is a person who is responsible for __________ other swimmers and protecting them from accidents.