【单选题】What advantage did the 20th century have over the 19th century?
A.
The new invention of the train made traveling possible.
B.
Information could be spread immediately.
C.
People didn’t get as much exercise anymore.
D.
Travelling by boat was still dangerous.
【简答题】原子弹和核反应堆的主要燃料 ,其原子核内有 个质子, 个中子,核外有 个电子。
【简答题】低于国家等级的普通水准测量,称为____,又称五等水准测量。(答案为6个字)
【单选题】21th century is a century of telecommuting.
【简答题】U ab 是否表示a端的电位高于b端电位?
【简答题】低于国家等级的普通水准测量,称为______,又称五等水准测量。
【单选题】大菜是由高档材料或()的原料烹饪而成的菜肴。
【单选题】Not until the early years of the 19th century ___ know what heat is. [ ]
【判断题】U ab 表示a端的电位高于b端的电位。