蛋白质生物合成的抑制剂是
A．磺胺
B．利福霉素
C．甲氨蝶呤
D．氮杂丝氨酸
E．卡那霉素
参考答案：E
- ______ he _____ on the farm(农场)?
-Yes, he does. He's a good farmer.[ ]
A. Does, work
B. Is, working
C. Does, do
农业劳动利用率
s a good farmer.[ ]