1. For centuries, people (believe) …………in the …………of UFOs.(exist) 2. I (help) ............................. if I could, but I’m afraid I can’t. 3. When I was young, I enjoyed (take) ............................. to the zoo. 4. I would suggest that your company (tell) .......................... your drivers to clear up all the trash on the ground before leaving. 5. In the past, Viet Nam’s education system (affect) ............................ by many cultures, of which the Chinese and French had most significant influence. 6. Environmental pollution has led to (appear) ............................... of many species of plants and animals from the Earth. 7. Nuclear power plants (efficiency) ........................... produce large amounts of electricity without polluting the atmosphere. 8. Although the Internet is one of man's (greatly) ........................ creations, it also has many disadvantages.