I ate ____sandwich while I was waiting for ____20:08 train.
The e-mail, as well as the telephone, ______ an important part in daily communication.
Jumping out of ______airplane at ten thousand feet is quite _____exciting experience.
What they need ______ enough money, while what we need ______ enough workers.
– Do you know William failed the exam, Jenny? -- _____? As far as I know, he is always working hard.
When you communicate with people, it is not unusual to find yourself in a situation ____ you have to politely decline an offer.