It’s said that Armstrong sent a message to Mission Control _____ said that two huge, strange objects landed near them and were watching them. A. who B. which C. whom D. whose 答案:B如图10-7所示,电路中ab是一段长10cm,电阻为100Ω的均匀电阻丝.两只定值电阻的阻值分别为R1=80Ω和R2=20Ω.当滑动触头P从a端缓慢向b端移动的全过程中灯泡始终发光.则当移动距离为____cm时灯泡最亮,移动距离为_____cm时灯泡最暗.