题目

The scientist is to attend the meeting ______ in the Great Hall of the People.A. to be having     B. to be held      C. to hold      D. held 答案：B张强同学参加学校举行的春游爬山活动，眼看山崖就在眼前．可走了好一会儿也没到山崖，张强和小明合作，想测一下他们距山崖还有多远，他拉响一个“拉炮”，小明计时，结果过了4s，他们听到回声．那么他们距山崖还有多远？