--- Is it convenient to you if I call you up at 9 o’clock tomorrow morning?

--- I’m afraid not. I _________ a speech then.

A．was giving

B．will be giving

C．am giving

D．will have given

“六一”儿童节前，全市的小学生代表用棱长3cm的正方体塑料拼插积木在广场中搭起了一面长6m，高2.7m，厚6cm的奥运心愿墙，算一算这面墙共用了多少块积木？