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。

Only then_______ how much damage had been caused.

she realized

she had realized

had she realized

did she realize

“only＋状语”位于句首，整个句子用不完全倒装．此外，由then可确定用过去时态．

I found _____ convenient to shop online at home .

it’s 

that

it

that was

考查强调句。句意：我发现在家网购很方便。这里it指代后面的to shop online。其中的强调句式是：主语+find it +形容词+to do，意为主语发现做某事是...的，故选C。

---Shall I tell Jhon about it?

---No, you            . I've told him already.

needn't

wouldn't

mustn't

shouldn't

考查情态动词。句意：---要我告诉约翰这件事情吗？--不，不必了，我已经告诉他了。A.needn't不必；B. wouldn't不会；C. musn't禁止，不允许；D. shouldn't 不应该。根据“I've told him already”，可知这里是“不必要”。故选A项。

There are 24 solar terms in a year. Grain Rain often starts in Apirl,the           month of the year.

Third

fourth

fifth

sixth

考查数词。句意：一年有24个节气。谷雨通常在一年中的四月开始。空格前有定冠词the,与可数名词单数month，要用序数词。根据

Grain Rain often starts in Apirl，可知四月份是一年之中的第四个月，要用序数词fourth。故选B项。

The salesman scolded the girl caught         and let her off.

to have stolen

to be stealing

to steal

stealing

考查非谓语动词。句意：这个销售员责备了被抓住正在偷东西的女孩，然后，让她走了。分析句子结构，caught是过去分词作定语，修饰前面的名词 the girl,"女孩"和"偷东西"之间是主动关系，用现在分词作宾语补足语，构成catch sb doing sth结构。意为抓住某人正在做某事。故选D项。