【简答题】钠的第一电离能高于钾,但通过下列反应却可以制备金属钾。为什么? KCl(熔)+Na=NaCl(熔)+K
【单选题】静态平衡训练法不包括()
E.
站立位(扶平衡杠站、独立站、单腿站)静态平衡训练法不包括
【单选题】Most amphibians hatch from eggs laid in water or moist ground, and begin life ____ water-dwelling larvae.
【简答题】n 已知:有一个长度为 1GB 的数据块,在带宽为 2Gbit/s 的信道上连续发送,且已知传输信道长度为 2000km ,信号在介质中的传播速度为 3.0×10 5 km/s ,求总延时。
【单选题】According to the speaker, why do pesticides pose a threat to amphibians?
A.
Pesticides can cause an amphibian's skin to dry out.
B.
Pesticides kill the insects that amphibians depend on for food.
C.
Dissolved pesticides can easily enter amphibian's bodies.
D.
Amphibians may eat plants that have been treated with pesticides.