If anyone happens to drop in while I am out, _________ him or her leave a message.
It is believed that if an event is __________,it will surely __________ the readers.
Readers were pleased __________ that a scientist could write about his research in a way __________ ordinary people could understand.
-Coach, can I continue with the training? -Sorry, you can't __________ you haven't recovered from the knee injury.
You can't be careful enough to drive on the __________ road in __________ weather.
That is the only way we can think of __________ the overuse of chemicals in agriculture.