－My parents         our home for a few hours when I arrived. I didn’t meet them.

－You could call them if you wanted to know where they were.

A．have been away from

B．had been away from

C．had left

D．had gone

以下无免疫抑制作用的药物是：

A．干扰素

B．左旋咪唑

C．硫唑嘌呤

D．糖皮质激素

E．环孢素