Like other animals, we are          until we know it is safe to relax.

on purpose

on fire

on guard

on duty

考查介词短语辨析。句意：像其他动物一样，我们在知道安全的时候才放松警惕。A.on purpose 故意；B. on fire着火；C.on guard 警惕；D.on duty值班。结合后文we know it is safe to relax，可知我们在知道安全的时候才放松警惕。故选C项。

Since this accident has nothing to do with him, he seems no way             .

to be blamed

to blame

blame for

to blame for

考查固定用法。句意：既然这次事故与他无关，他似乎也就无可指责了。短语sb to be blame“某人该受责备，某人应该负责”，为固定搭配，没有被动语态。故选B项。

The black teacher set a good example ____ all the rest of the group, _____ all peace-loving people.

to, who are

for, which was

to, which are

to, who were

[翻译]黑人教师给其他所有爱好和平的人树立了一个好榜样。[解析] D 解析：set an example to表示给某人树榜样，由此可以排除B;因先行词指人，故使用who引导非限定性定语从句，由此可以排除C; 根据时态的一致原则可知，此处应当使用一般过去时，故正确答案为D项。

Though it is a          job, he  still devotes much time and energy to it.

poor-paying

poorly-paying

poorly-paid

poor-paid

考查构词法。本题中考查了复合形容词的构词法，“使用副词+过去分词” 构成新的形容词，如“newly-discovered”最新发现的；本句中“poorly-paid报酬极少的”。句意：尽管这是一份报酬极少的工作，但他仍然花了很多时间和精力做它。故选C项。

Wouldn’t it be         wonderful world if we lived in         harmony with nature?

a; /

the; /

a; the

the; the

考查冠词和短语。句意：如果我们与自然和谐相处，这不是一个美好的世界吗？第一个空中，world表示泛指，应用不定冠词且wonderful发音为以辅音音素开头的单词，故应用a;第二空短语in harmony with表示“与....和谐”，中间不加冠词。故选A项。

It was not until 1920 ___ regular radio broadcasts began.

when

which

that

since

此题考查强调句。句意为：直到1920年，常规的电台才开始。这句话把it is/was和that去掉后，仍是完整的一句话，因此我们可以知道这是一个强调句，而且是对not...until“直到...才”的强调。结构是：it is/was+not until+其他成分。故选:C.

Inside the window hangs a         carved out of this piece of wood by the artist.

decoration

destination

departure

discipline

考查名词辨析。句意：窗户边上挂着一幅被艺术家由这块木头雕刻的装饰品。A. decoration装饰，装饰品；B. destination目标； C. departure 离开；D. discipline纪律。窗边应挂着装饰品。故选A项。

While we may not be born with a nature talent, we can          for it with hard work.

break up

take up

bring up

make up

考查动词短语辨析。句意：虽然我们可能没有与生俱来的天赋，但我们可以通过努力工作来弥补。A. break up打碎；B.take up 拿起，开始从事；C.bring up提出；D. make up 弥补。根据上文we may not be born with a nature talent可知没有与生俱来的天赋，所以要通过努力工作来弥补。故选D项。

Though ____ the dangers of smoking to their health, smokers still find it hard to give up smoking.

aware of

are aware of

be aware of

考查状语从句的省略：句意：虽然很多经常吸烟的人已经意识到抽烟对他们健康造成了很严重的后果，但是他们仍然发现很难戒烟。Though引导的让步状语从句是省略句，完整的句子是：though smokers are aware of the dangers of smoking to their health。当主从句的主语一致的时候，可以省略从句的主语和be动词，选B

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。