15世纪中期灭亡拜占廷帝国的是 [ ]
A．亚历山大帝国
B、法兰克王国
C、阿拉伯帝国
D、奥斯曼帝国
答案：D
用must, mustn't, can, can't填空。
1. Don't open your present now! In China you _____ wait and open it later.
2. —Can I do cleaning at Spring Festival?
—No, you_____ .
—It's bad luck.
3. In America you _____ open your present immediately.
You don't have to wait!
4. In Britain you _____ ride your bicycle on the pavement _____. It's too dangerous.
5. In Britain, you _____ be 18 if you want to drive a car.
端末效应
Spring Festival?