When           another country, you should be aware of those differences and respect them.

visit

to visit

visiting

visited

考查非谓语动词。句意：当拜访另一个国家时，你应该知道这些不同之处并尊重它们。分析句子可知，空格处应填非谓语动词和when一起构成时间状语，逻辑主语you和visit之间是主动关系，应用现在分词。故选C项。

Only when he returned ________ that the war had ended and the army had come back.

we tell

we told

did we tell

were we told

考查倒装句型。Only放在句首时，句子要用倒装语序；根据句意“我们被告知”可知，此处要用were we told。故答案选D。

The teacher was so pleased with the progress that I had        in my study this term that she sent me an English-Chinese dictionary.

made

had 

kept

graded

考查动词辨析。句意：老师对我在这学期在学习上取得的进步非常满意，寄给我一本英汉词典。分析可知hat I had        in my study this term 应是之前名词the progress的定语从句，先行词在从句中属于固定结构make progress“取得进步”的宾语。故选A项。

The old rules have to be          because they only applied to the circumstances that existed when they were made a hundred years ago.

developed

established

observed

revised

考查动词的辨析。句意：老的规则需要被修改因为它们只适合一百年制定时的状况。A.develop发展；培养；B.establish建立；C.observe观察；D.revise修改，由because they only applied to 可知它只适用于以前，需要修改。故选D项。

Tom looks so pale today. He ______ ill.

must be

had to be

should be

shall be

[翻译]汤姆看起来脸色不好，他一定生病了。[解析] A 试题解析：情态动词must表示推测。题目中表示肯定的推测。

_______ by keeping down costs will Power Data hold its advantage over other companies.

Only  

Just 

 Still  

Yet

考查倒装句式。句意：只有通过降低成本，Power Data才能比其它公司更有优势。A只有；B仅仅；C仍然；D然而。Only加副词、介词短语或时间状语，放句首时，用部分倒装。故选A。

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。