写出下列英语词组。
1. 做某事困难
2. 经常复习
3. 集中注意力去做某事
4. 标出重点部分
5. 一条建议
6. 提高记忆能力
7. 有机会去做某事
8. 和别人交流
9. 宁可, 宁愿
10. 不同的学习方法
1. have a hard time doing sth.
2. review regularly
3. concentrate on doing sth
4. highlight the important parts
5. a piece of advice
6. improve your memory
7. have a chance to do sth
8. communicate with sb
9. rather than
10. different learning styles