Linguists find that all languages change ( ) time -- albeit at different rates, in three main aspects: vocabulary, sentence structure and pronunciations. 2. Apart from the source of energy, a nuclear energy plant is ( ) essence no different from any fossil fuel power plant. Both use the energy source to generate heat to drive turbines that generate electricity. 3. Soon after the New Year, the new Congress will come to Washington to be sworn ( ). 4. Many people swear ( ) vitamin C's ability to ward off colds. 5. The fate of a project which could revolutionize the use of computers in hospitals hangs ( ) the balance.