— How do you often spend your summer holidays?

— I often go hiking, for I like ________ nature. [      ]

A. getting close to  

B. getting away from

C. getting along with  

D. getting together with

并发执行有可能引发的问题不包括______。

A．丢失(更新)问题
B．脏数据问题
C．不可重复读取问题
D．事务读取冲突