VOA慢速英语:Making Better Concrete With Rice?

Once引导状语从句

once用作连词时，意为“一旦……就……”，用于连接时间状语从句，相当于as soon as。如：

Once you start, you will never give up. 一旦你开始了，你就不要放弃。

Once you begin to read it, you will like it. 一旦你开始读，你就会喜欢它。

Physics is easy to learn once you understand the rules. 一旦你理解了规则，物理就不难学了。

注意：once引导的是时间状语从句，从句要用一般现在时代替将来时。

out of a job失业，没用

He was out of a job for six months.
他已失业半年了。

2. Carbon is driven out, and fine particles of almost pure silica remain.

drive out把…赶出去,驱逐,驱赶

例句：I watched him drive the cattle out.
      我看着他把牛赶出去。

      They drove foreign goods out of the market.
      他们把外国货驱逐出市场。

3.Also, the inventors say the light-colored material better reflects sunlight, so buildings would cost less to cool.

light-colored是合成词，颜色浅的

4.Using it could make the most sense in areas where farmers grow lots of rice and the hulls might just go to waste.

make sense有道理；有意义；讲得通

例句：This sentence doesn't make any sense.
      这个句子没有意义。

      It doesn't make any sense to get up so early.
      那么早起来没有任何意义。