在松软地层中钻进时，管棚应设定外插角，角度一般不宜大于（）。
A.7°
B.5°
C.9°
D.3°
参考答案：D
In order to finish the experiment successfully, the professor always _________, for every day the light in his room didn’t go out until 4 a.m.
A．mixed up
B．cleaned up
C．turned up
D．stayed up
曾经被一条大狗咬过的人，看见非常小的狗也可能产生恐惧。这是( )
A．刺激泛化
B．刺激分化
C．刺激获得
D．刺激消退
