— What should I do when I feel weak and tired all day?
— _______ some food like beef may be helpful.
A:Eat
B:Eating
C:Ate
D:Eats
构成我国地势第二和第三阶梯分界线的山脉由北向南依次是( )
如图甲是小明同学安装好的直流电动机模型: