How they had completed the construction in time / as planned remained / is still a mystery.

　　5） 他能否按时到达，现在还不得而知。

　　It is not yet known／It is hard to say whether／if he will arrive／come on time.

　　6） 人们认为饭后散步有助消化。

　　It is believed that taking a walk after meals promotes digestion / is good to your stomach.

　　7） 他说的与事实完全相反。

　　What he said was totally opposed to the facts.

　　8） 科学家正在研究为什么白日梦（daydreaming）会有益于人们的健康。

　　Scientists are studying why daydreaming is beneficial/conducive to people‘s health.

　　9） 他的肤色与他是否是个好教授没有关系。

　　The color of his skin is irrelevant to whether he is a good professor or not.

　　10） 那位生物学家相信某些动物物种正受到灭绝的威胁。

　　The biologist is convinced / believes that some animal species are faced with the danger of extinction.

　　11） 我不知道他是否能够提供有力的证据。

　　I wonder if he can provide positive proof.

　　12） 爱因斯坦声称物质和能量是可以相互转化的，因此没有绝对的时间和空间。

　　Einstein claimed that matter and energy are interchangeable， so there is no absolute time and space/so time and space are not absolute.

　　13） 最新的研究成果表明，白日做梦是日常生活的一部分。

　　Recent research indicates that daydreaming is part of daily life.

　　14）你所说的与我们正在讨论的豪不相干。

　　What you said has nothing to do/has no relevance with what we are discussing.

　　3. 定语从句

　　1） 一个具有文学艺术欣赏力的人能胜任这项工作。

　　A person who appreciates / A person with appreciation of art and literature is qualified for the job.

　　2） 处理这项事务的政府部门没有做统计。

　　The government department that deals with this does not keep statistics.

　　3） 短缺并未严重到你报道的那种程度。

　　The shortage do not exist to the extent that you report.

　　4. 比较级和最高级

　　1） 快速旅行对人体的影响比我们意识到的要大得多。

　　The effects of rapid travel on the human body are much greater than we realize.

　　2） 一个社会的人口增长率越接近零，其人口便越老龄化。

　　The nearer a society approximates to zero population growth， the older its population is.

　　3） 近年来，计算机在各个领域的应用越来越广泛。

　　In recent years， the computer is finding wider and wider application in all fields.