【单选题】Enough attention should be paid to ______ your pronunciation and intonation in the study of English.
【单选题】一I still cannot figure out why he missed his flight. 一He an accident on the way to the airport.
【单选题】Mr .Smith ______ the first bus, otherwise he should have arrived here by now.
【多选题】下面有关等高线的说法,正确的是()。
B.
等高线是闭合曲线,如不在本图幅内闭合,则必在图外闭合
C.
等高线平距小,表示坡度缓等高线平距大,表示坡度陡。
E.
除在悬崖或绝壁处外,等高线在图上不能相交或重合。
【单选题】The best way ______ your English is ______ grammar. [ ]