_____ we celebrate a festival it changes a little and in that way we keep our culture alive．
| A．Some time | B．Each time | C．From time to time | D．Many a time |
Hiking is _____ great fun. You will get close to ____ nature and take exercise at the same time.
| A．a; the | B．a; 不填 | C．不填；the | D．不填；不填 |
I couldn't imagine ______difficult it was for these badly injured victims to make it to the hospital.
| A． when | B．how | C．what | D．where |
—Where did you get this book?
—I picked it up from a second-hand bookshop if you ______know.
| A． must | B．will | C．can | D．shall |
—What are you two whispering about over there?
—Oh, ______. Just small talk.
| A．no | B．nobody | C．none | D．nothing |
When I ______home, I caught a thief stealing from a passer-by.
| A．headed | B．was heading | C．has headed | D．had headed |