It was last night ________ I saw the comet.

the time

when

that

which

强调句的结构是：It＋be＋强调部分＋that(who)＋主谓句。强调句的连词只有两个，that和who。当强调的部分是人，且为句子的主语时，才用“who”，其余用that。因此选C。

Tom wanted to play football with his friends in the street，but his father told him ________.

not to

not to do

not do it

do not to

考查动词不定式的省略。完整的形式应该是…，but his father told him not to play football with his friends in the street.为避免重复，常省去不定式动词，保留不定式符号to，故选A。

It's really           to know that there're only seven bones in giraffes' long necks.

amazingly

amazed

amazing

amazement

考查形容词辨析。句意：知道长颈鹿的长脖子上只有7块骨头，真是令人惊讶。分析句子结构可知，is是系动词，空格处需填形容词作表语。主语是It,指物，表示“令人惊讶的”，应填amazing。故选C项。

Lucy tried to help, but she was          as if she was  interfering, not helping.

dynamic

compulsory

scared

clumsy

考察形容词。句意：露西想要帮忙，但她笨手笨脚，好像在干涉别人，而不是在帮忙。A.dynamic动态的；B. compulsory 义务的；C.scared 害怕的；D.clumsy笨拙的。结合后文好像是在干涉别人，而不是在帮忙。可知露西笨手笨脚的。故选D项。

It was along the Mississippi River _________ Mark Twain spent much of his childhood.

how

which

that

where

此处构成It was...that...强调句式，句中强调了介词短语along the Mississippi River。故选C。