香气的三要素：香气量、香气质和（）。
参考答案：香型
向氨水中加入NH4Cl晶体，溶液的碱性
A．增强
B．减弱
C．不变
D．为零
The result of another study involved phone-use questionnaires shows that ______.
A．brain cancer patients don't incline to use cell-phones
B．cancer-free participants like to use cell-phones
C．significance of cell-phones
D．cancer-free participants seldom use cell-phones
