Happiness is (21) everyone looks for. Maybe someone says that he is (22) . However, what makes him happy may not (23) for Others. And even worse, someone may spend all his (24) looking for happiness, but in vain(徒然). In the past, I tried my best to (25) myself happy. I thought if I could freely get and do what I wanted to, I (26) be happy. Certainly, it was possible but I was (27) Though I could be happy at times, I couldn’t keep my happiness for a long time. Why One day, when I told a friend of mine what I (28) about happiness, he smiled and said only a few words, "Happiness is not a single thing but a by- product(副产品)." I was surprised, but he was really (29) Someone thinks money can (30) everything, but when he becomes a millionaire after his work, perhaps he (31) find that he has new (32) . And he has to go to church for (33) . Sometimes love can bring happiness, (34) at other times it (35) misunderstanding, tiredness, and even quarrelling. Happiness is only a by-product of all (36) of things you love to do. You can not grasp it in a (37) way. That is, it is not a thing existing in material form but in your senses. You should tell yourself, "I do not (38) whether I’m happy or not. But I must love my life." And one day you will suddenly find happiness (39) has quietly (40) .

21（）

A．what
B．that
C．which
D．it