选择括号内恰当的单词或词组填入空白处，使句意完整、正确。
— Light pollution is_________(harm/harmful) to our eyes.
— You are right.
— How long has she learned English?
—She has learned English _________(for/since) over two years.
—In most countries             (nodding/ shaking) the head means agreement.
—That’s right.
—You needn’t pay me anything. But please do everything you can        ( help / to help) those in need.
— OK. I will try my best.
—Tom, come over and _______(take off / take away) your clothes.
—Sorry, mom. I’m doing my homework now.