【C18】A．is beingB．areC．have beenD．is

The president is believed__________ seriously ill．A.beingB.to beC.been##

To say something _______ one thing, to do it _____ another.A、is; isB、are; areC、is; areD

【C11】A．beingB．beenC．areD．is

War and peace______a constant theme in history.A．isB．areC．had beenD．have been

One or perhaps more pages ______ missing.A．isB．areC．has beenD．have been

【C10】A．beingB．areC．beD．were