It was not until 1920 ___ regular radio broadcasts began.

when

which

that

since

此题考查强调句。句意为：直到1920年，常规的电台才开始。这句话把it is/was和that去掉后，仍是完整的一句话，因此我们可以知道这是一个强调句，而且是对not...until“直到...才”的强调。结构是：it is/was+not until+其他成分。故选:C.

Really? You        twice the price to buy the book!

paid

took

spent

cost

考查动词词义辨析。句意：真的吗？你付了2倍的价格买这本书！四个动词都有“花费”的意思，但用法不同。pay的主语通常是人，常用结构是 sb pay (money) for sth;take作“花费”时讲常用于固定句型 It takes/took sb (money/time)to do sth做某事花费某人（金钱/时间）；spend的主语通常是人 sb spend...on sth 或sb spend ...(in) doing sth;cost的主语通常是物，sth cost sb (money)意为“某物花了某人多少钱。本题主语是人，结合句意和后文to buy the book，空格处应填pay。故选A项。

If you work hard like this, you will           sooner or later.

give out

break up

break down

fall down

考查动词短语。句意：如果你继续这样辛苦工作的话，你迟早垮掉。A.give out分发 ；B.break up打碎；C.break down垮掉；D.fall down 跌倒。根据句意可知break down符合语境。故选C项。

I would really appreciate       if you can make time in your schedules to attend my lecture today.

that

it

this

one

考查形式宾语。句意：如果你今天能从日程安排中抽出时间来听我的讲座的话，我将不胜感激。I would appreciate it if/when...如果/当...时，我将非常感激。it 做形式宾语。故选B项。

it was at 10 pm yesterday______he came home from work.

that

when

which

what

考查强调句。句意：昨天晚上10点他下班回家。考查it+be+强调部分+that+句子，选A。