_____is a question scientists have yet to answer.

"I haven’t seen you for a long time".

"How_____ such an expensive dress?"

The people at the party were worried about Janet because no one was aware_____ she had gone.

"Do you know Don Kline?"

"I remember the name but I can't remember_____"?

_____ in large quantities is not necessarily an indication of its quality.

The function of "That clause" in "The basis for this American custom is that most parents teach their children_____"

Is this_____ you asked him for?

They always give the available seats to _____ comes first.

"Why doesn't Kurt get his hair cut?"

"I don’t know_____"

"Call the restaurant and ask for that information"

"I don't remember_____"

"The postal strike started today"

"_____something to prevent it?"

Scientists are attempting to find out_____ there is life on other planets.

Punish_____ is late.

Because of the rain, people are calling to ask_____ take place.

"I'm looking for the mail. Do you know_____?"

"Usually it comes by 4:00"

"Why did you talk to the teacher after class?"

"I didn't understand_____ during the lecture".