A study shows the students who are engaged in after-school  activities are happier than        who are not.

ones

those

these

them

考查代词。句意：一项研究表明，参加课外活动的学生比不参加课外活动的学生更开心。空格处代词与the students是对应关系，可以用the ones 或者those替代。“them”指代前面提到的复数名词，不能与the students形成对应关系，“these”一般不用定语从句修饰。故选B项。

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。

Writing out all the invitations by hand was more time-consuing than we             .

will except

are  excepting

except

had excepted

考查时态。句意：手工写下所有的邀请函要比我们预料的花去更多的时间。根据句意可知我们预料是在实际上写之前发生的，而本句中实际写花去的时间使用了过去时was，所以expect用过去完成时。故D项正确。

If you see things in a negative light, you will find faults everywhere and problems where there are really          .

none

some

many 

nothing

考查代词辨析。句意：如果你用消极的眼光看待事物，你会发现到处都是问题。A. none没有任何东西；B.some 一些；C.many 许多；D.nothing 无事；无物。此处指没有问题的地方也有问题·。故选A项

          is a pity           you didn't attend the lecture last night. It was wonderful.

What; that

It; that

What; why

It; why

考查固定句型。句意：很遗憾，你昨晚没去听讲座。那太美妙了。此处为句型“It is a pity that.....”，表示“遗憾的是....", It 作形式主语，that 引导主语从句是真正的主语，从句句意完整，成分齐全，that不做成分，仅起引导作用。故选B项。