I planted some fruit trees last year but they (wouldn't) grow because they didn't get enough sun.去年我栽了些果树,可它们就是不长,因为没有得到充足的阳光.这里选择B.wouldn't应该是一种语气词 其他几个答案都不合适 A.mustn't一 定不能 C.shouldn't 不应该 D.might not