【判断题】高炉煤气的主要成分是CO,其次是CH4、H2。
【单选题】Which of following description related to “Kennedy’s moon-shot speech” is NOT true?
A.
Kennedy is US President John F. Kennedy.
B.
The speech was held on May 25, 1961.
C.
Kennedy challenged Congress and the American people to put a man on the moon
D.
Kennedy was sent to the moon.
【单选题】The place where a channel moves from along one bank of the river over to the other bank of the river is called a().
【简答题】共阳极的数码管输入信号的有效电平是 [填空(1)] 电平。
【单选题】系统性能调整的手段包括______。 ①数据查询调整与优化 ②索引调整 ③数据库模式调整 ④DBMS和操作系统参数调整 ⑤数据库应用程序优化 ⑥硬件配置调整和升级 A) ①②④⑤⑥ B) ①②③⑤⑥ C) ②③④⑤⑥ D) ①②③④⑤⑥
【单选题】The new bridge over the river is ____.
【简答题】共阳极的数码管输入信号的有效电平是 [填空(1)] 电 平。A. 低