某41肽被水解成2个8肽，2个6肽，1个4肽，3个3肽，这些短肽的肽键总数是[ ]
A．31
B．32
C．33
D．34
答案：C
We had to _________ the engine piece by piece for transport.
A．take up
B．take out
C．take off
D．take apart
验电器A带正电，B不带电，用一根金属棒将它们连接后，电流方向从验电器______到验电器______，电子移动方向从验电器______到验电器______．
