选出你所听到的句子( )
A:Young people's memories are better than old people's.
B:Young people usually have better memories than old people.
C:Young people usually have bad memories than old people.
Fire is very dangerous. It can ____people. We ____be careful with fire. We mustn't play near fires. We mustn't play with matches. We mustn't ____in the forest. When we see a fire, we must go outside ____,but ____use the lift.