The past two years ______a sharp rise in oil price, which adds to the burden of auto transportation industry.
| A．has witnessed | B．witnessed | C．is witnessing | D．witnesses |
Without proper lessons, you could _____ a lot of bad habits when playing the piano.
| A．give up | B．catch up | C．pick up | D．keep up |
It suddenly _____ to me that we could ask our neighbors to help us.
| A．thought | B．happened | C．came | D．occurred |
The father as well as his three children _____ skating on the freezing river every Sunday afternoon in winter.
| A．is going | B．go | C．goes | D．are going |
He kept looking at her, wondering whether he _____ her somewhere.
| A．saw | B．has seen | C．sees | D．had seen |
When the soldier _____ his shirt, he discovered that his arms were black and blue.
| A．took on | B．took over | C．took in | D．took off |