While listening in class, you should concentrate ____ your teacher.
Peng Liyuan, First Lady of China invited Obama’s wife and his children to visit China March, 2014.
---I’ll try harder next time.---You have said it one hundred times. But _____.
---Boys, don’t swim in the Fengcheng River!---Why not? Isn’t it deep enough _____?
Whether we will hold the sports meet _____ the weather.
If we don’t save energy, it _____ some day.