The officer insisted that Michael did not follow the correct ________ in applying for a visa. (2012·湖北,30)
Reagan was elected ___ of the United States in 1981.
This is the best film __ we have seen this year.
He has a poor memory.He has forgotten ___ his dictionary while reading.
They devote themselves to __ a new way to make populated water clean.
Bamboo is ___ grass, but not tree.