问题：
.
According to some doctors, one of the ways to prevent us from growing old is to make sure
that our brains get enough___.
A．performance
B．exercise
C．experience
D．sport
.
According to some doctors, one of the ways to prevent us from growing old is to make sure
that our brains get enough___.
According to some doctors, one of the ways to prevent us from growing old is to make sure
that our brains get enough___.
| A．performance | B．exercise | C．experience | D．sport |
参考答案：