Stop cutting trees, _______ the earth will become worse and worse.
Simon has spent _____ on his study , but the result of his study isn’t ______.
______ blue clothes _____ good for your mind.
You can stay here , _______ you can leave at once.
.----I’d like a cup of black coffee. What about you, Maggie?--- I prefer coffee______ sugar.
They thought ________ important to look left and right when ________ the road.