Dark clouds are a ___of rain while a smile a ____of friendship.
You may________it that he will turn up in time.
The old man told me that this kind of plant didn’t need________.
She has been warning________the danger of driving the car________a high speed.
________about Jane,the teacher called her parents to find out why she was often absent from school.
As modern equipment is being used widely,the factory________some of its workers with robots.