推土机液压操纵系统推土板操纵杆有（）、下降、停止、浮动四个位置。
参考答案：提升
To see if his new bike works properly, Jane could hardly wait to _____.
A．turn it out
B．carry it out
C．try it out
D．work it out
胆结石不可出现（）
A.右上腹或剑突下疼痛
B.腹胀
C.肠梗阻
D.食欲减退
