I had been puzzled over the problem for over an hour without any result, ____ all at once the solution flashed across my mind.
The reason _______ he was absent from the meeting is_____ he suffered from a headache.
Everyone knows that _____ is dangerous to play with fire, but _____ is difficult is to prevent children from playing with fire.
—I am thinking of the test tomorrow. I am afraid I cannot pass this time.—_________! I am sure you will make it.
As the clock struck nine, players ______their positions and the match began.
—Lucy, read this book, I ____ that you’ll be fond of it.—OK. I’ll read it after I have finished my homework.