用所给单词的适当形式填空，一格一词。
【小题1】There are three ______(knife) on the desk.
【小题2】We know the ________(important) of learning English well.
【小题3】Yesterday, I_____(give) away my old bike to the little child.
【小题4】Thank you for your______(kind).
【小题5】Suddenly, I ______（understand）his meaning.