The new discovery _______ be of great service to mankind.
A、isboundtoA
beboundto：注定要，一定會。本題中主語是Thenewdiscovery，所以謂語動詞要用is。句意：這項新發現對于人類必定大有用處。
Water is composed _______ hydrogen and oxygen.
Theboycomplained_______apaininhisstomach.
_______foryourlaziness，youcouldhavefinishedtheassignmentbynow.
Thetwogirlscompetedwitheachother______thehighestmark.
Thecentraltheatrehasaseating________ofmorethan3,000people.
