Once you _____ the knack of it, you will have no further difficulty.A.shall haveB.had h

This is a piece of very important news. You must have it ____ to your country at once

______ it is you ve found, you must give it back to the owner of it.A．WhicheverB．WhatC．Wha

When once you have had the disease, you are______ to it for the rest of your life.A．immune

It was very kind of you to do the washing up yesterday, but you______it.A．mustn"tB．wouldn"

Once environmental damage_____, it takes hundreds of years for the system to recover.A．has

Once you _____ the knack of it you will have no further difficulty.A.shall haveB.had h