Is he three years old?
Is he younger than you?
Is he nine years old?
Does he look younger than his age?请标出是哪道题的谢谢现在只有你能救我命了1. who is (he)? (he )is my (younger brother)Is he your younger brother?2. how old is (he)?(he) is(3)years（younger）thanIam..Is he 3 years younger than you?3. is（he）（9）years old？ yes，（he）is （he）looksyoungerthan （his） ageDoes he look younger than his age?