About________percentoftheearth'ssurfaceiscoveredwithwater
Thenumberofsecondsinoneday_____Thenumberofminutesinoneweek
Ihaveapenfriend，andwealwayssende_____toeachotherbycomputer
Therearesomanypeopleintheshop.Youmust________yourthings.
Thereare_____studentsinourclass.Thatis19boysand21girls。