Tom，together with Mary and Alice，______swim this afternoon．
| A．is going to | B．are going to | C．was going to | D．were going to |
______I be free tomorrow，I could go with you．
| A．Could | B．Should | C．Might | D．Must |
______stopping polluting the earth______hope to live in a better environment．
| A．Only to；we Call | B．Only to；can we | C．Only by；can we | D．Only by；we can |
You______be tired—you've only been working for an hour．
| A．must not | B．won't | C．can't | D．may not |
Father______for London on business upon my arrival，so I didn't see him．
| A．has left | B．left | C．was leaving | D．had left |