为明确诊断，最有价值的辅助检查是（）
A.免疫学检查
B.肌肉活检
C.肌电图检查
D.血清肌酶检查
E.食道钡餐检查
参考答案：B
Children’s brains can’t develop properly_______ they lack protein.
A．when
B．since
C．because
D．unless
One of the basic rules of computer security is to change your（73）regularly.
A．name
B．computer
C．password
D．device
