Please check out the following sentences. Are they grammatical?
1. Thomas Edison, America's most famous inventor, took out over 1000 patents during his lifetime.
2. Reared up in an environment of rural poverty, Jerry Lee Lewis displayed a talent for music from an early age.
3. Only in the past decade have sun-bathers begun to understand the risk of skin cancer associated with excessive exposure to the sun's harmful rays.
4. The meaning of some words will change depending on the context in which they are used.
5. The largest city in the state, Philadelphia, Pennsylvania, was founded by William Penn in the late 17th century.