选出恰当的应答语( )
A:I'm fine,thanks.
B:I'm ten years old.
看图片,选句子
A. Talk quietly.
B. Keep to the right.
C. What is Zhang Peng doing?
D. Keep your desk clean.
E. They are eating lunch.
____
在直角坐标系xOy中,角α的始边为x轴的非负半轴,终边为射线l:y=22x(x≥0).求cos(α+π6)的值;
一名中学生的质量约是50____;
一根头发的直径是:70____.