血清最好的除菌方法是
A．煮沸法
B．滤过除菌法
C．高压蒸气灭菌法
D．紫外线照射法
E．巴氏消毒法
参考答案：B
- John and I will celebrate our forties wedding anniversary next month.
- Oh, _________ !
A．cheer up
B．well done
C．go ahead
D．congratulations
Discovery in a South African cave suggests that modern human behavior ____ much earlierthan ____.
A．begin, previously thought
B．began, previously thought
C．should begin, previous thinking
D．began, previous thinking
