Our grade held the grown-up ceremony on March, 21st, _____ I have been well aware of my responsibility

for our society. [ ]

A. when

B. during which

C. since then

D. since when

下列各项中，所给数据与实际情况最接近的是（　　）

A．我国壹角硬币的厚度接近1cm

B．人拿起一个鸡蛋的力大约是1N

C．成年人的裤长接近0.5m

D．人步行的速度约为1m/s