少年期的三大生理变化,指的是[ ]
①性机能发育成熟②身体外形急剧变化③体内机能迅速健全④思想更加活跃
A、①②④
B、①②③
C、①③④
D、②③④
答案:B
—Have you figured out how much the tuition is in American universities?
—$19,000, or _____like that
A.anything
B.everything
C.nothing
D.something
铝热焊作业两端各15米紧固扣件,撤除焊缝两侧各()根轨枕扣件。
A.2-4
B.3-5
C.3-6