船舶在浅水区航行时，通常会出现：（）.Ⅰ船速下降Ⅱ船体下沉和纵倾Ⅲ舵效变差Ⅳ首向浅滩一侧偏转
A.Ⅰ～Ⅳ
B.Ⅰ～Ⅲ
C.Ⅰ、Ⅲ
D.Ⅱ、Ⅳ
参考答案：B
-- Doctor! I can’t fall at night.
---Don’t worry! You are too stressed. Just be relaxed and take some pills, then you’ll be better.
A．sleepy; asleep
B．asleep; sleeping
C．sleep; sleep
D．asleep, sleepy
若∠A、∠B、∠C是△ABC的三个内角，∠A：∠B：∠C=1：1：2，则△ABC是______三角形．
