People who take less exercise seem more vulnerable to illness.
缺少运动的人对疾病的抵抗力就差。
No one can call back yesterday;Yesterday will not be called again.
昨日不复来。
And so with solids such as a shell, a nut, a plum, a pear, a tadpole, a mushroom, a mountain peak, a kidney, a carrot, a tree-trunk, a bird, a bud, a lark, a ladybird, a bulrush, a bone.