stretch one's legs：散步、走几步放松筋骨

　　e.g. I'd like to stretch my legs after a day's work.

2、role：角色、职务

a leading role：主角；

play / take an important role in ...：在......里扮演重要角色

e.g. He will play the role of the doctor in the play.

China is playing a more and more important role in international affairs.

What role will the actress play?

3、practise：vt. / vi. 练（习）、实习、行/做业务，用 "practise (doing) sth".句式。

e.g. You have to practise the tune again and again.

You must practise speaking English more.

I can guess that you don't practise enough.

He has practised law for years.

practice：n. 练习、习惯做法（不可数）， vt. / vi. = practise

e.g. Practice makes perfect.

With practice you will speak English fluently.

It's my practice to get up early in the morning.

practical：实际的、实用的、老练的

practical knowledge：实用知识

　 for all practical purposes：实际上

a practical teacher：经验丰富的教师

practiced：有经验的， be practiced in...：在某方面有经验、熟练

4、ensure：vt. 担保（成功）、保证

1) ensure sth.

e.g. Registration ensures delivery of mails.

Hard work usually ensures success.

2) ensure sb. sth.

e.g. Healthy diet and proper exercise will ensure you a good health.

This letter of recommendation will ensure you a job.

3) ensure that ...：保证......一事

e.g. I can't ensure that you'll have the job for long.

Get on the bus and I ensure that you'll have a seat.

4) ensure (sb./ oneself) against ...：保护某人不受......

e.g. We should ensure ourselves against possible risks.

Proper exercise will ensure one against some diseases.

5、keep ... under control：控制住、使......处于控制之中

e.g. Soon the pilot kept the plane under control.

A good teacher should keep his / her class under control.

control：un. 支配、控制

have control of / over sth.：对......的控制

e.g. The teacher has no control of the class.

The captain has got control over the new football team.

beyond control：无法掌握、无法控制； in control of：管理、掌握

in the control of：被......控制、管理 lose control of：失去对......的控制