重點講解:
1. be centered on (使)以…為中心;(使)注意力集中于;
Attention was centered on the figure of the president.
所有的注意力都集中在總統的外形上。
2. so far 迄今為止;到目前為止;
His whereabouts have been utterly unknown so far.
迄今他的下落全然未知。
3. depend on 取決(于);有賴(于);
Whether we'll go on a sightseeing trip tomorrow will depend on the weather.
我們明天是否出游,得看天氣。
4. clear out 清理;
How long will it take you to clear out the sentox?
你可以用多長時間清除毒氣?
n. 有價證券;擔保;保證人;抵押物(security的