把17本书放进3个抽屉，有一个抽屉至少要放______本．
17÷3=5（本）…2本．
5+1=6（本）．
答：有一个抽屉至少要放6本．
故答案为：6．
用反射式探伤法探伤，缺陷越大反射回波越强。
—Have you seen Dr. Adams recently?
—No. He __________ Hong Kong for an international meeting. He’ll come back tomorrow.[ ]
A. has gone in
B. has been in
C. has gone to
D. has been to
