英语that指代问题

题目

英语that指代问题
1.The problem of pollution in this city is more serious than ___ in other cities.
A.that B.it C.this D.those
2.It is much more sandy in Beijing than ___ in spring and early summer.
A.in Tianjin B.that in Tianjin C.Tianjin D.it in Tianjin
答案都是A,为什么第二题不能选B

答案

that指示代词,而且只指代名词,所以在第一题中可以指代 “The problem of pollution ”,第二题就不同了,里面没有可以指代的名词,所以就不能用“that”了