---I ________ this morning，but he could not come．

---Well，we'd better go and _________ at his office．

A.called him；call on him

B.called on him；call him

C.called at him；call

D.called him；call at him

答案及解析： A

解析：

call可表示“给……打电话”，根据会话的语境，第一空应填 called him；

call on sb．表示“拜访某人”，是固定搭配.答案为A.