You can only be sure of_____you have atpresent;you cannot be sure of somethingyou might get in thefuture

In fact fuels we burn and plant food we eat ________ their chemical energy in the form of heat.

— I have come to say good-by.— What time_____?[ ]

It is uncertain side effect the medicine will bring ?about?,although about two thousand patients have taken it. [ ]

d you give up the job inAustralia—-Because I don’t want to stay far away from my family You know, my familymeans ______ to me