617. witness n. 目击者；证据 vt. 注意到；证明

This country has previously witnessed two great struggles to achieve a truly multicultural democracy. (2006年6月17日大学英语四级(CET-4)真题试卷(A卷))

618. withdraw v. 收回，撤销

Mother withdrew $100 from her account.

妈妈从账户上取出100美元。

619. slippery a. 滑的

Many falls are due to wet floors or slippery rugs.

很多摔伤事件是由于湿地板或滑的地毯所致。

620. smash vt. 粉碎，打烂

My watch was smashed against the wall.

我的手表撞在墙上破碎了。

621. snap n. /vt. 折断，拉断；快照

Here is some of our holiday snap.

这些是我们的上些假日快照。

622. software n. 软件

As a result of its strength in science, the United States has consistently led the world in the commercialization of major new technologies, from the mainframe computer and the integrated circuit of the 1960s to the Internet infrastructure （基础设施） and applications software of the 1990s. (2007年12月大学英语四级考试真题)

623. solar a. 太阳的

Unlike solar or wind power, heat from the rocks is always on.

和太阳能或者风力不同的是，地热随时都可以取用。

624. lunar a. 月的，月球的

He patiently waited , then when I was done , he said he would like Chinese New Year did not begin January first , and that Chinese New Year ,which is tied to the lunar cycle ,is one of the most celebrated holidays on the Chinese calendar . （2009年6月英语四级考试真题）

625. submerge vi. 潜入水中

The whole village and the fields have been submerged by floods.

洪水已淹没了整个村庄和农田。

626. submit vi. (to)屈服，听从

Applying for artistic merit scholarships usually requires that students submit a portfolio(选辑)of some sort, whether that includes a collection of artwork, a recording of a musical performance or a video of them dancing. （2009年12月大学英语四级考试试题）

627. timber n. 木材，原木

There's more timber to transport now.

现在有更多的木材需要运输。

628. tissue n. 组织；薄纱，手巾纸

Food and drink leave traces in one’s body tissues. （2009年6月英语四级考试真题）

629. title n. 题目，标题

Newsweeklies, women’s titles, and business magazines have all seen increases in advertising because they attract the high-end market （2008年6月大学英语四级考试真题）

630. tone n. 语气，音调

He kept the tone of the letter formal and businesslike.

他使这封信保持正式公文的语气。

631. drift vi. 漂，漂流

A fleecy cloud was drifting past.

一朵白云正在飘然而过。