Those naughty boys were punished because they were caught ________ flowers in the garden.
句意： 那些调皮的男孩受到了惩罚， 因为他们被撞见在花园里偷花。sb. be caught doing sth.表示“碰上、 撞见、 发现某人做某事”， 其主动结构为catch sb. doing sth.。