【根据句意，用所给单词的适当形式填空。1.Weallknow______________(pollute)waterdoesharmtoourhealth.2.Ihavereadfive(twelve)ofthisbook.3.Ifyouareinabluemoodyoucando】

　　根据句意，用所给单词的适当形式填空。

　　1.Weallknow______________(pollute)waterdoesharmtoourhealth.

　　2.Ihavereadfive                 (twelve)ofthisbook.

　　3.Ifyouareinabluemoodyoucandoyourhobbiestocheer               (you)upboys.

　　4.Totellyouthe                (true)Ifeltsadwhileyouwereaway. 

　　5.Thechildrenheardthe                (frighten)shoutandlookedateachotherinfear.