What I wanted to know was when and where the meeting .A. was holdingB. had heldC. was to h

问题补充：

What I wanted to know was when and where the meeting .

A. was holding

B. had held

C. was to hold

D. was to be held

答案：

A. was holding

B. had held

C. was to hold

(答案→)D. was to be held

解析：从逻辑上说，“会议”应是被开，故用被动式。