—OK．I will do it right now．

PCl₃、POCl₃的部分性质如下：

某兴趣小组模拟该工艺设计实验装置如下(某些夹持装置、加热装置已略去) ：

⑴Let me help you .____                           A、No , I can't .

⑵Are we all here today ?____                  B、No , thanks .

⑶Is that bag light ?____                           C、No , he isn't here .

⑷What day is it today ?____                    D、Certainly .

⑸Is it heavy ?____                                    E、No , it is heavy .

⑹Who's on duty today ?____                  F、I am .

⑺Can you carry it ?____                          G、Yes , it is .

⑻Could you help me , please ?____       H、OK .

⑼Thanks a lot .____                                 I、You're welcome .

⑽Let's put the books in the box .____    J、It's Tuesday .

某反应为2X+2SO₂+O₂→2CaSO₄+2CO₂，X的化学式是（  ）