B型题造成下列乳剂不稳定现象的原因是 转相（）
A. Zeta电位降低
B. 分散相与连续相存在密度差
C. 微生物及光、热、空气等的作用
D. 乳化剂失去乳化作用
E. 乳化剂类型改变
What does the woman mean（）
A. She knows the guy who will give the lecture.
B. She thinks the lecture might be informative.
C. She wants to add something to her lecture.
D. She’ll finish her report this weekend.
What does the man say about Bob（）
A. He’s been to Seattle many times.
B. He has chaired a lot of conferences.
C. He has a high position in his company.
D. He lived in Seattle for many years.
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