Choose the best answer.

The fire was so important to early cultures that scientists now study it to learn more about ancient civilizations.

Choose the best answer.

If a machine stops moving or working normally, you can say that it has ______ .

Find the mistake.

Perhaps the most distinctive features of insects and undoubtedly one of the most important reasons for their success is their quite well-developed sensory system.

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You may find doing this job very _______. Try it!

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In 1791, Pierre-Charles L' Enfant ________ plan for the new capital city at Washington.

Choose the word CLOSEST in meaning to the underlined part.

The architect was let down that his new city plan had been turned down.

Choose the word OPPOSITE in meaning to the underlined part.

Vietnamese have a strong sense of hospitality and feel embarrassed if they cannot show their guests full respect by preparing for their arrival.

Choose the best answer.

Turn off this machine, please. The harsh sound really _______ me crazy.