1.by + 可数名词:
by the hour/day/week/month 按小时/日/周/月
by the piece 按件,计件
by the square metre 按平方米
by the dozen 按打
by the kilo/gallon 按公斤/加仑
by the hundred 一百一百地
2.by + 不可数名词:
by weight/volume 按重量/体积
by age,sex,and height 按年龄,性别和身体高度
3.in + 复数名词:
in calories 按卡路里
in hundreds 几百几百地
in five hundreds 五百五百地