【简答题】差分放大电路的主要作用是放大 信号,抑制 信号。
【单选题】科学家在某种植物中找到了抗枯萎的基因,并以质粒为运载体,采用转基因方法培育出了抗枯萎病的金茶花新品种,下列有关说法正确的是 [ ]
A.
质粒是最常用的运载体之一,它仅存在于原核细胞中
B.
将抗枯萎基因连接到质粒上,用到的工具酶仅是DNA连接酶
C.
用叶肉细胞作为受体细胞培育出的植株不能表现出抗枯萎性状
D.
通过该方法获得的抗病金茶花,产生的配子不一定含抗病基因
【单选题】I'm sorry you've been waiting so long, but it'll still be some time ________ Brian gets back.
【简答题】a. I'm not sure whether I can drive well b. drive within the speed limit c. You must use your turn signals d. what are the basics e. You must stop completely at red lights and stop signs A: Sorry I'm ...
【单选题】程序段 G01 G02 GOO G03 X50.0 Y70.0 R30.0 F70;最终执行( )指令。
【单选题】差分放大电路的主要作用是抑制( )信号。
【简答题】A: Excuse me, I think that's my umbrella you've ____1______. B: Oops. I didn't _____2_____. Here you are. I'm very sorry. A: It doesn't matter. They just look much _____3_____.