A:attend
B:take part in
C:join
D:join in
7>
含有遗传物质,能传递遗传信息的细胞结构是
如图,身高为1.6m的某学生想测量一棵大树的高度,她沿着树影BA由B到A走去,当走到C点时,她的影子顶端正好与树的影子顶端重合,测得BC=3.2m,CA=0.8m,则树的高度为____m.
There ______ a large number of students in our school. The number of the students _______ over three thousand.