9. leap [ li:p ] vi. to jump 跳跃

The young deer was leaping about the meadow.
小鹿在草地上跳来跳去。
As soon as he caught sight of the police, he leapt to his feet and fled away.
他一看到警察撒腿就跑。

10. run after 追赶，追逐

Run after your father, he's forgotten his hat.
快追你父亲，他把帽子忘了。
Look! A dog is running after a rabbit!

11. drop [ drRp ] vi.

(1) to fall 降落，落下，掉下
An apple dropped from the tree.
He labored so hard that a lot of sweat dropped from his brow.
他工作如此辛苦，汗水不停地从他的额（眉）上滴落下来。

(2) 下降;降低；变弱
The production of sugar dropped because of the limited demand.
由于需求有限，糖产量下降了。
His voice dropped to a whisper.
他的声音低落成耳语。

12. hop [ hRp ] vi.

(1) to move with a light springing motion（蛙,鸟等）齐足跳跃；齐足跳行
The birds came hopping round my window.

(2) 跳；弹跳
The ball hopped around the playground.

13. pick up 拣起，拾起

He bent down to pick up the apple on the ground.
My pen has fallen down on the ground. Please pick it up for me.

14. dust [ dQst ] v. to remove dust from 掸灰尘

She dusts once a week.
He picked himself up and dusted himself down.
他爬起来，弹掉身上的灰尘。

15. in time 及时

Students should review their lessons in time in order to grasp what is taught.
You'd better go to see a doctor immediately, or your wound will be infected.
你最好赶快看医生，否则你的伤会感染。

16. turn [ t[:n ] vi.

(1) 转动，转向，转弯
He turned and walked away.
He heard his name called but didn't turn.
他听到有人喊他，但他没转身。

(2) 变化，改变
Soon, her sorrow turned to joy.
很快她的悲哀变成了快乐。
My luck has turned at last.
我终于时来运转了。

17. crumble [ krQmbl ] vi. & vt.

(1) vi. to break into small pieces 崩溃，倒塌
After years of neglect, his house began to crumble.
放置几年后，他的房子开始倒塌。

(2) vt. 弄碎,打碎
The quake crumbled the walls of the hospital.
地震使医院的墙壁倒塌。