下列哪些药物可抗疟原虫（）

A.磷酸氯喹

B.甲氟喹

C.青蒿素

D.氯喹注射液

E.氟哌酸

---Where’s your father?

---He __________ to Singapore for a meeting. He ________ there twice.

A．has gone, has been

B．has been, has gone

C．has gone, has gone

D．has been, has been