meters
You would use kilograms (kg) to measure someone's mass in metric units.
Kilometers
To measure the distance across a lake, you would typically use kilometers or miles, depending on the scale of the lake and the preference for metric or imperial units. For smaller lakes, meters may also be appropriate. Using these units allows for a clear understanding of the distance involved.
Celsius degrees
To measure a soccer field in the metric system, you would use a metric measuring tape or a measuring wheel. The units used could be meters or centimeters. In the English system, you would use a tape measure or a measuring wheel calibrated in feet or yards. The units used would be feet or yards.
Meters
You would use kilograms (kg) to measure someone's mass in metric units.
inches or centimeters, I would use inches.
Kilometers
What metric unit would you use to measure a computer keyboard
distance
To measure the distance across a lake, you would typically use kilometers or miles, depending on the scale of the lake and the preference for metric or imperial units. For smaller lakes, meters may also be appropriate. Using these units allows for a clear understanding of the distance involved.
A ruler
This information is already posted at Wikipedia as follows: http://en.wikipedia.org/wiki/Metrication_in_Australia
Litres
Celsius degrees
It would probably be miles.