The result of the experiment was ……………..

A number of ……………. submitted their manuscripts under pseudonyms to conceal the fact that they were women.

Some executives require that the secretary …………….. responsible for writing all reports as well as for balancing the books.

Although a doctor may be able to diagnose a problem ………………, he still may not be able to find a drug to which the patient will respond.

This law is purely ……………...

The number of the days in a week …………….. seven.

Although the red cross accepts blood from most donors, the nurses will not ………….. you give blood if you have just had a cold.

Most comets have two kinds of tails, one made up of dust, ……………… made up of electrically charged particles called plasma.

By 1820, there were over sixty steamboats on the Mississippi river, ……………… were quite luxurious.

The native people of the Americans are called Indians because when Columbus landed in the Bahamas in 1492, he thought that he …………….. the east Indies.