Thinking of solving problems: According to life experience, we can know that the thickness of a math textbook is measured in millimeters according to the length, weight unit and data size; Measure a hippo and reuse "tons" as a unit; My height is in meters and centimeters, and my weight is in kilograms. Judging from this.

This math book is 7 mm thick.

A hippopotamus weighs about 4 tons.

I am 1.35 cm tall and weigh 30 kg.

So the answer is: millimeters, tons, meters, centimeters, kilograms.

Fill in the appropriate units in the horizontal line.

The math book is 7 _ _ _ _

A hippopotamus weighs about 4 _ _ _ _

My height1_ _ _ _ 35 _ _ _ _, and my weight is 30 _ _ _ _.