Sentence 1 is in passive voice
400 pt is less than 100 gal
Nick refers to Tom and Daisy Buchanan as careless people because he's witnessed them ruin lives and simply disappear by hiding behind their wealth.
If you mean reading skills then read daily for 20-30 minutes, practice is the most important factor. If you do not know how to pronounce any word then search it on youtube. Read out loud near your friends and family members to improve it.
