_______ on your study, and you will make greater progress．
| A．Concentrating | B．If you concentrate |
| C．Concentrate | D．To concentrate |
---Guys, I was really worn out! I cant walk any further!
--- We should have a rest. We ______ the cave a whole day.
| A．exploring | B．are exploring |
| C． have been exploring | D．explore |
Seeing the happy ______ of students playing basketball there, I cant help thinking of my school years.
| A．view | B．sign | C．sense | D．scene |
Mrs Smith is a boss, ______company my uncle is devoted.
| A．to whom | B．to whose | C．whose | D．of which |
---Why didnt you tell him about the meeting?
--- He rushed out of the room ______ I could say a word.
| A．until | B．before | C．when | D．after |
Toms words on which our decision was ______ werent true.
| A．base | B．basing |
| C．to be based | D．based |