2. (5 points) 1 ton $=$ $\qquad$kg = $\qquad$g, is a $\qquad$ unit.
1 liter $=$ $\qquad$ml, is a $\qquad$ unit.
$1 \mathrm{~km}=$ $\qquad$ m = $\qquad$ $\mathrm{cm}$, is a $\qquad$ unit.
【Answer】Solution: 1 ton $=1000$ kilograms $=100000$ grams, is a unit of mass.
1 liter $=1000$ milliliters, is a unit of volume.
$1 \mathrm{~km}=1000 \mathrm{~m}=100000 \mathrm{~cm}$, is a unit of length.
Therefore, the answers are: 1000, 100000, mass; 1000, volume; $1000, 100000$, length.