20．Many scientists believe that robots able to talk like humans in 50 years.
A. were
B. are
C. will be
D. have been
【答案】 C
【解析】【分析】考查动词的时态。句意：许多科学家认为，五十年过后，机器人将能够像人类一样说话。描述“五十年后”将要发生的动作或状态，用一般将来时态。故选C。
21．— Have you finished writing your book?
— Yes. It _______ and _______ soon.
A. is printing; is coming out
B. is being printed; will come out
C. is going to print, will be come out
D. is printed; has come out
【答案】 B
【解析】【分析】句意：你写成你的书了吗？是的它正在印刷，并且很快就要出版。被动语态表示主语是动作的承受者，即行为动作的对象。例如：English is spoken by many people.主语English是动词speak的承受者。被动语态由“助动词be＋及物动词的过去分词”构成。进行时态的结构：be being done,soon 不久，很快，将来的时间，故第二个空用将来时态，故选B。
【点评】考查语态和时态的用法。
22．- Tommy, do you know if Frank ______ to the theatre with us this Sunday if the weather ______.
- Sorry, I have no idea.
A. will go; is fine
B. goes; is fine
C. will go; will be fine
D. goes; will be fine
【答案】 A
【解析】【分析】句意：——托尼, 你知道如果明天天气好, 富兰克林是否与我们一起去剧院。——对不起, 我并不知道。根据do you know if Frank 可知, if在动词后面, 它引导的是宾语从句, 表示“是否”．当主句是一般现在时态或含情态动词的句子, 宾语从句应该根据需要选用任何时态．此句由this Sunday 可知, 动作还没有发生, 所以用一般将来时态, 排除BD；又根据Frank ______ to the theatre with us this Sunday if the weather ______可知, if引导的是条件状语从句, 当主句是一般将来时态, 从句应该用一般现在时态表将来, 我们称这一现象为“主将从现”, 排除C．故选A。
【点评】一般将来时；一般现在时
23．Stop smoking, Joe! You yourself if you keep on doing it like that!