下列说法最科学的是( )
A:现代的食品保鲜方法就是添加防腐剂
B:保持正常的呼吸是贮存食品的重要方法
C:乳酸菌发酵过程中能产生乳酸和二氧化碳
D:白酒的酿造过程中利用了霉菌和酵母菌两种微生物
A: Who's that ____( boy / girl) ?
B: He's my brother.
A: Is the ____( man / woman) your mother?
B: Yes, she is.
A:____ (What's / Who's) that man?
B: Guess.
A: Is ____( he / she) your father?
B: No, he isn't.____ (She's / He's ) my teacher.