It was shortly after that serious accident happened ______ all the people involved were caught and questioned.

A. since               B. that                 C. before              D. when

The remains of adventurer’s private airplane were reported ______, but the adventurer remained missing.

A. being found          B. to be found         C. having found        D. to have been found

Some companies are thinking of ways to save natural _____ by making better use of the water used in the bathroom.

A. resources            B. sources               C. power           D. energy

After seven successful flights, China’s next spacecraft Shenzhou VIII _______to pave the way for building a permanent space laboratory.

Since the baby milk powder was found to be polluted, there has been universal doubt _____ other food products are safe to eat. 

A. whether             B. that                C. what             D. how

In 1888, the world's first beauty contest was held in Belgium. Though _____ is known about the competition, the idea caught on.

A. everything          B. nothing             C. much             D. little  

Recent scientific studies indicate that eating healthy food and exercising regularly ____ help prevent many diseases.

A. might              B. can              C. shall               D. will      

 _____ Ashley made her first public performance on Broadway, her whole family went to see it.

A. Though            B. Once             C. When              D. As long as

 Experts say that the rate at which one ages ______ from person to person and is usually influenced by a number of factors. 

A. is varying         B. varied             C. has varied           D. varies

The Olympic _____ remind us of where the Olympics are held and the characteristics of the host country.

A. symbols          B. signals             C. marks              D. signs