A Lesson in a Lab
⑤tom was supposed to have stolen the money.
湯姆被認為偷了錢。
13.—the plane ________arrive at 11∶30，but was almost half an hour late.
—common practice.
a.was about to b.was likely to
c.was supposed to d.was certain to
解析：選c。be supposed to do“本應該”。
【即境活用】
★14.the message is very important，so it is supposed________as soon as possible.
a.to be sent b.to send
c.being sent d.sending
解析：選a。句意：這條信息很重要，所以要盡快發出去。be supposed后接不定式結構，意為“理應，應該”，排除c項和d項。it 指message，message和send之間為被動關系，排除b項，故a為正確答案。
句型梳理
① 【教材原句】 it is hard to think of a world without metals.(p44)
很難想象一個沒有金屬的世界。
【句法分析】 本句中，it 為形式主語，真正的主語是不定式短語to think of...，構成it is/was＋adj.＋to do sth.的結構。
it is ＋adj.＋for sb.to do sth.該句式中，作表語的形容詞只能說明不定式的行為性質和特點，不能說明不定式的執行者。常見的這類形容詞有：easy，important，difficult，hard，possible，impossible，necessary等。
it is＋adj.＋of sb.to do sth.該句式中，作表語的形容詞表達不定式的邏輯主語的品行、性格或性質。常見的這類形容詞有：kind，nice，good，honest，careful，careless，clever，wise，stupid，foolish，rude，polite，impolite等。
it is＋adj./n.＋thatclause
it is＋no good/use doing sth.
①it is easier to say than to do.說比做容易。
②it is no good playing computer games.玩電腦游戲沒有好處。
③it is a shame that he didn’t pass the exam.
很遺憾他沒有通過考試。
④it is said that the tickets have been sold out.
據說票已售完。
15.(XX年高考大綱全國卷ⅱ)the doctor thought______would be good for you to have a holiday.
a.this b.that
c.one d.it
解析：選d。句意：醫生認為度假對你有好處。本題考查代詞it作形式主語。根據句意不定式短語to have a holiday在賓語從句中作真正的主語，只有it 可作形式主語，故選d項。
【即境活用】
★16.(XX年高考天津卷)it is obvious to the students________they should get well prepared for their future.
a.as b.which
c.whether d.that
解析：選d。句意是：對學生來說，很明顯的是他們應該為將來做好準備。it是形式主語，________they should get well prepared for their future是主語從句，作真正的主語。這個引導詞起引導作用，不作成分，故用that。
② 【教材原句】 here is a table with the metals that react most at the top，and the metals that react least at the bottom.(p44)
這兒有一個圖表，那些反應最強烈的金屬在上部，反應最不強烈的在下部。