掘进机开机时应（）。
A.打开各转载点喷雾装置
B.开启抑尘装置
C.发出报警信号
D.甩掉保护
参考答案：A, B, C
In spite of his wealth , he is not happy. (选出与其意思相同的句子)[ ]
A. Rich as he is , he is not happy.
B. Although he is wealth , he is not happy.
C. Although he is rich , but he is not happy.
D. Although he is not happy, but he is rich.
某医生比较两种不同手术治疗某病的疗效，共收治患者71例，结果如下表
经统计处理得到以下结论（）
A．χ2=4.45P＜0.05，两种手术不同
B．χ2=3.06P＞0.05，两种手术相同
C．χ2=20.45P＜0.05，两种手术不同
D．χ2=5.28P＜0.05，两种手术不同E．χ2=1.36P＞0.05，两种手术相同
