—Remember the first time we met, Jim?—Of course I do. You ________ in the library.
----- Must I turn off the gas after cooking? ----- Of course. You can never be ______ careful with that.
He told me he had been offered a well-paid ____, but he refused it.
He has written a lot of books, but ______ good ones.
Everyone here will thank the firefighters for the things they do to prevent fires ______ the environment safer.
If Newton lived today, he would be surprised by what ______ in science and technology.