系统交付用户使用以后,直到报废为止的所有软件活动都属于系统( )
A.运行阶段
B.维护阶段
C.评价阶段
D.运行维护阶段
参考答案:D
用括号里所给单词的适当形式填空
1. I’m looking forward to (see) you soon.
2. My uncle (work) in that restaurant.
3. A (care) driver often causes (引起) a traffic accident.
4. There (be) heavy rain tonight.
5. Table tennis is (popular) than running.
人体的每个细胞都能利用氧气将 等有机物分解,产生二氧化碳和水,并释放能量。这个过程就是 。