制作馒头、面包利用的微生物的生殖方式是：[ ]
A．营养生殖
B．无性生殖
C．种子生殖
D．有性生殖
B
简述光学经纬仪对中、整平的步骤。
According to Skinner, a well-known behaviorist psychologist, ______, was much more effective than ______ in a teaching situation.
A. reward...reasoning B. reward...punishmentC. reasoning...reward D. reasoning...punishment
