【单选题】—Can you tell me ______? —Two weeks ago. [ ]
A.
how much the computer cost
B.
who you made the toy for
C.
how many CDs did you buy
D.
when you bought the camera
【简答题】炉子刚启动时,炉墙形成的温度场为___________温度场,经过较长时间后,形成_____态温度场。
【判断题】炉子刚启动时,炉墙形成的温度场为稳态温度场,经过较长时间后,形成不稳态温度场。 ( )
【简答题】归于液泡系的细胞器有()、()、()()(),共同特征具有( )层单位膜。