Farmers often employ fertilizer or other special chemicals to _____the growth of crops, as is well-known.

. It is said that his carelessness and ignorance together ________ a terrible fire, which burned down the building.

A good listener takes part in the conversation,offering ideas and ___ questions to keep the talk flowing.

“Geili”, created from the two Chinese characters “gei” and “li”, _______ a word only spoken in some dialects, but now it _______ something cool or exciting all over the country. 

He was _____ down for some days after he heard that he didn’t pass the exam.