用适当的介词填空
1. My mother is very kind ________ her pupils.
2. You should be very friendly ________ the poor.
3. Can you help me ________ my English?
4. My cousin lives ________ the USA.
5. Don't be late ________ class again.
6. I have been ________ the Great Wall three times.
7. She is angry ________ him, because he hasn't finished his homework.