He always has great trouble (understand)______what the teacher says in class.

A．The shopping center is a bit far away.
B．He doesn’t know how to get to the shopping center.
C．The shopping center is just around the comer.
D．He only knows one way to the shopping center.

A．It is a dream which many people can hardly realize.
B．It is so expensive that many people cannot really buy them.
C．It is the most important property that many people try to buy.
D．It doesn’t belong to people if they can’t borrow money from the bank.