________about Jane，the teacher called her parents to find out why she was often absent from school.
| A．Concerning | B．Concerned |
| C．To be concerned | D．Concern |
Whether it will do us harm remains_______ .
| A．seen | B．seeing | C．being seen | D．to be seen |
There, in the corner, sat three girls,_______.
| A．sew | B．were sewing | C．to sew | D．sewing |
_______the early train,you'll have to get up early and rush in a taxi.
| A．Catching | B．Caught | C．To catch | D．Catch |
The_______waiter came up to us and said,"You are welcome."
| A．smiling | B．smiled | C．smile | D．to smile |
There is a big dog_______to a fence outside the house.
| A．tying | B．tied | C．to tie | D．ties |