If oil supplies run out in 2050 then we need to find ______ energy sources soon.

Scientist are warning that human activity is starting to cause ____ in the Earth’s climate due to increasing temperatures.

She said she had a headache. Otherwise, she ______ in the dance.

She ______ herself on cooking Vietnamese traditional dishes.

By the time Brown's daughter graduates,_______retired.

I don't think Peter will reject that job offer, ___________?

The temperature ________ takes place varies widely from material to material.

I _______ the living room by the time Dad comes home. He will be surprised.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.

    The investors bought a deserted warehouse __________ convert it into a shopping mall for the townspeople.

My dog as well as my cats ______ twice a day.

I haven’t been up into the attic for twenty years. Anything ______ be up there!

More and more investors are pouring money into food and beverage _______ start-ups.

Extinction means a situation ______ a plant, an animal or a way of life stops existing.

You are allowed to go to the party ______ you don’t stay out too late. Remember to be back here no later than 11.30 p.m.

The noise in the hall was terrible but he just _____ on speaking as if he couldn’t hear it.