Not that I’m unwilling to lend you a hand , ____I’m too busy for the moment .

So although Fleming discovered penicillin, it was over a decade ___________someone else turned penicillin into the great drug of the 20th century.

 ________ he stops driving himself like this, he'll have a breakdown.

The second-hand car she bought was almost new ,______,it was in good condition.

There is a new problem involved in the popularity of private cars________road conditions need________.