继发性雷诺综合征的病因（）
A.结缔组织病
B.原发性肺动脉高压
C.卒中
D.β-受体阻滞剂
E.硝苯地平
参考答案：A, B, C, D
Strong typhoons strike this area very _____. Normally, they form and come here between July and
August every year. [ ]
A. generally
B. regularly
C. usually
D. suddenly
※ [29～30]
. (4 )
A．
B．
C．
D．
