城乡居民生活用电电价执行范围是直接用于（）居民生活的用电。
A.城镇
B.农村
C.城镇或农村
D.城镇和农村
参考答案：C
A recent survey shows that the number of children who from the countryside with their parents ________nearly 320,000 in Beijing.
A．comes; are
B．come; is
C．come; are
D．comes; is
柴油机气缸盖、气缸套和活塞冷却水腔的锈蚀是()。①化学腐蚀②氧化还原反应③电化学腐蚀
A.①
B.②
C.⑧
D.①②③
