促进液体在固体表面铺展或渗透的作用称为()
A.增溶
B.乳化
C.助溶
D.润湿
E.潜溶
参考答案:D
The two friends _____ on the Internet for three hours, and they would go on till the next morning.
A.had been chatting
B.had chatted
C.were chatting
D.has been chatting
呼吸系统最常见的症状是()
A.咳嗽
B.咽喉肿痛
C.高热
D.心动过速
E.胸痛