【用括号内所给动词的适当形式填空。1.Afteraknockatthedoorthechildheardhismother'svoice_____(call)him.2.It'snogood_____(waste)strengthinshouting.3.Ourgroupismainlyconcernedwithbir】

　　用括号内所给动词的适当形式填空。1.Afteraknockatthedoorthechildheardhismother'svoice_____ (call)him.

　　2.It'snogood_____ (waste)strengthinshouting.

　　3.Ourgroupismainlyconcernedwithbird_____ (conserve)incoastalareas.

　　4.Hefeltembarrassedwithsomanyeyes_____ (focus)onhisclotheshewaswearing.

　　5.ThechildrentalkedsoloudlyatdinnertablethatIhadtostruggle_____ (hear).