Question

When you are planting trees, the trees ________ straight in the hole. A．must put B．must be .

When you are planting trees, the trees ________ straight in the hole. A．must put B．must be put C．are putting D．is put

Answer 1

B

试题分析：句意为：植树的时候，树必须直立放到坑里。根据语境，句子的主语是“the trees”，是动作的承受者，应用被动语态。故选B。