Small sailboats can easily turn over in the water ________.

if not managed carefully

if are not managed carefully

unless not managed carefully

unless are not managed carefully

There                   in the world              China is a great country with a long history and rich culture.

are no doubt; that 

are not doubts; if

is no doubt; that

is not doubt; if

考查固定句型和同位语从句。句意：毫无疑问，中国是世界上有着悠久历史，丰富文化的一个大国。分析句子可知，这个句型为 there is no doubt that 引导，表示“毫无疑问......”.本句为that that 引导的同位语从句，句意和句子结构完整。故选C项。

Her         for writing was a desire for women to get  the right to higher education.

motivation

qualification

talent

technique

考查名词词义辨析。句意：她写作的动力源自为女性获得更高教育的权利。motivation动力；动机；qualification资格；talent才能，天赋；technique技巧。故a desire for women to get  the right to higher educatio是她写作的动力。故选A项。

I drink a cup of coffee           ; but usually I take tea.

frequently

often

constantly

occasionally

考查副词词义辨析。句意：我偶尔喝一杯咖啡，但我通常喝茶。A. frequently频繁地；B.often经常地；C.constantly连续不断地；D.occasionally偶尔地。but 表转折关系；根据后半句的usually,前面用occasionally,与usually意思相对。故选D项。

If you want to catch the first bus you'd better         for the bus station immediately.

set up

set about

set down

set off

考查动词短语辨析。句意：如果你想赶上第一班公交车，你最好马上动身去车站。A. set up建立；B. set about开始做.....;C. set down 记下；D. set off 出发，动身。结合上文If you want to catch the first bus you'd better可知此处指“动身，出发”，应用set off。故选D项。