According to scientists, our mental abilities begin to ___ from the age of 27 after reaching the highest level at 22.
_________school work, I spend most of my spare time singing and dancing.
My brother has been preparing carefully for the English exam, so that he can be sure of passing it at his first _______
I’m sorry you’ve been waiting so long, but it’ll still be some time ______ Smith gets back.
----How long will you stay in Peking University? ---- I don’t know. ________.
We ______ last night, but we went to the concert instead.