The information tells me that the way of education in Canada is quite different from          in China.

one

it

that 

those

考察代词。句意：这条信息告诉我们在加拿大的教育方式和在中国的教育方式很不一样。前后比较的是教育方式，用that 指代the+名词。A. one 是泛指一个，B.it 指的是同一个东西，D. those指代the +名词复数。故选C项。

— Is it my age ________the boss minds?
—I’m afraid so. He will consider ________ necessary to have an experienced assistant.

which；it

that；it

which；that

that；that

考查强调句型和it的用法。第一空that与it is构成强调句型。第二空it是一个形式宾语，真正的宾语是不定式to have an experienced assistant，选B。

Great amounts of water            poured into the river from the factories two years ago.

was

were

has been

have been

考查时态和主谓一致。句意：两年前，工厂将大量废水排入河中。根据two years ago 可知，句子使用一般过去时。....amounts of修饰不可数名词作主语时，谓语动词用复数形式，即谓语动词与amounts保持数的一致。故选B项。

The most important promises we must keep are          we make to ourselves.

ones

those

these

them

考查代词。句意：我们必须遵守的最重要的承诺就是我们对自己做出的承诺。A. ones泛指上文提到的可数名词复数；B. those特指上文提到的可数名词复数；C. these这些；D.them他们。分析句子可知，为we must 是定语从句，修饰The most important promises，是句子的主语；be动词后缺少表演，we make to ourselves是定语从句，修饰空格处。根据句意，此处指上文提到的promises,由定语从句修饰表示特指，故用 those。故选B项。