热力站的换热器不宜少于两台,当其中一台停止工作时,其余热交换器的供热量,应满足供暖系统负荷的70%,生活热水系统负荷的()
A.70%
B.50%
C.60%
D.80%
参考答案:B
用所给单词的适当形式填空。
1. He usually ___________ (go) climbing at weekends .
2. How many ___________ (country) do you know in the world?
3. Are they from different ___________ (class)?
4. ___________ ( Chinese) is the home of Confucius (孔子) .
5. Jack is from ___________. He speaks ___________ ( American)
下列关于栈的叙述中正确的是______。
A.在栈中只能插入数据
B.在栈中只能删除数据
C.栈是先进先出的线性表
D.栈是先进后出的线性表