IgA降低的是（）
A.反复呼吸道感染
B.湿疹
C.类风湿性关节炎
D.肾脏疾病
E.SLE
参考答案：A
_______ seems strange to us is ________ the clever boy failed in the exam.
A．It; that
B．What; what
C．It; how
D．What; that
焊接拉筋时应按什么顺序进行焊接？
