【判断题】如果样品在正相硅胶吸附薄层层析中展开时,Rf值过大,需要增大展开剂极性
【判断题】接地电阻是指电流经过接地体进入大地并向周围扩散时所遇到的电阻 。建筑物一般接地电阻小于等于30 Ω 。
【判断题】You can use the Undo command to reverse the last action you took.
【简答题】What can you infer from the last sentence of the first paragraph?
【单选题】M: Are you sure you can remember the name of the film you saw last week? W: It’s just on the tip of my tongue. SECTION C NEWS BROADCAST 18. What does the woman say about the film?
A.
It is hard to pronounce the name.
B.
It is not going to be well received.
C.
She has temporarily forgotten its name.
D.
She has never heard of the name.
【简答题】什么是教学的启发性原则贯彻启发性原则的基本要求有哪些