________ happens in the world makes us happy and sad by turns.
Listen to the two girls by the window. What language _____?
.Mary takes great ____ in learning pop music.
The computer system ____ suddenly while he was searching for information on the Internet.
Many students joined in the ____ race in the sports meeting to be held next week.
___ and out of breath, we reached the top of the mountain and stopped ____ the beautiful scenery.