The thought ______ he might fail in the exam worried him.
Ladies and gentlemen, please remain __________ until the plane has come to a complete stop.
We are invited to a party _________in our club next Friday.
_________ the right kind of training , these teenage soccer players may one day grew the international stars.
Nowadays people sometimes separate their waste to make it easier for it .
When he the door, he found his keys were nowhere.