Marie witnessed everything but it is amazing that she______ have said nothing about the murder.
| A．should | B．may | C．must | D．can |
The experiment shows that proper amounts of exercise, if ________ regularly, can improve our health.
| A．being carried out | B．carrying out |
| C．carried out | D．to carry out |
________ from the top of the tower, the south foot of the mountain is a sea of trees.
| A．Seen | B．Seeing |
| C．Have seen | D．To see |
________ at my classmates' faces, 1 read the same excitement in their eyes.
| A．Looking | B．Look |
| C．To look | D．Looked |
Though ________ to see us, the professor gave us a warm welcome,
| A．surprise | B．was surprised |
| C．surprised | D．being surprised |
The first snow didn't fall until February in our province this year，__________ was unexpected.
| A．it | B．which |
| C．that | D．what |