Unit 3 Inventors and inventions语言点
编稿：牛新阁 审稿：王春霞
学习目标
重点词汇
distinguish, convenient, expectation, seize, valid,
bear, tap, current, associate practical
重点短语
now and then, set out (to do), set about, call up, hang on, get through,
out of order, dive into, ring back/ ring off
重点句型
从when cooled说开来
only引出的倒装结构
