giúp em Exercise 1. Read the following passage and circle the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbers blanks. Are you looking for a cheap, clean, effective source of power that doesn't cause (1) or waste natural resources? Look no further than solar energy from the (2). At present, most of our electricity comes from the use of coal, gas, oil or nuclear power. This power could be provided by the Sun. One percent of the solar energy that reaches the Earth is enough to provide power for the total (3) energy. Solar panels are placed (4) Many countries are already using solar the roof of a house and the Sun's energy is used to heat water. 1. A. pollute pollution B. pollutes 2. A. Moon 3. A. popular Vietnam 4. A. on C. polluted D. B. Sun C. Earth D.March B. population B. in C. world D. C. of D. to