Water is much more precious than electricity, for the water for drinking is__________.
—Hi, Tom, why do you look so tired?—Because I ______ last night to finish my homework.
The underlined letter “ a” in the word “______” has different pronunciation (发音)from the others.
- ______ exercising, and you'll be healthier.
There______ a sport meeting in our school this weekend, isn't there?
- Don't forget to bring your homework here tomorrow.-_______.