F.1科學 20點 急急急要!!!

1) By using sedimentation, (a) colloidal substances that are (b) dissolved in water cannot be removed.

2) Boiling is a process that requires heat energy to change water into steam.

3) Using ozone for sterilizing swimming pools is more effective in killing (a) bacteria in water. In addition, ozone does not give off a (b) smell, and will not cause (c) irritations to eyes or skin.

4) In Hong Kong, water is treated at (a) water treatment plants before being supplied to us. The treated water is safe to drink. But it may pass through (b) rusted water pipes before reaching our homes. Thus, we have to (c) boil and (d) purify the water before drinking it.

1) By using sedimentation , (a)_mineral_______ substances that are (b) _dissolved_______ in watercannot be removed .

2) Boiling is a process that requires _heat energy_____ to change water into steam.

3) Using ozone for sterilising swimming pools is more effective in killing (a) _bacteria___
in water . In addition , ozone does not give off a (b) _smell___ , and will not cause (c) _irritation___ to eyes or skin .

4) In Hong Kong , water is treated at (a) _water treatment facilities______ before being supplied to us . The treated water is safe to drink . But it may pass through (b) _main___ water pipes before reaching our homes . Thus , we have to (c) _filter_ and (d) _boil___ the water before drinking it .