The conventional view that the Mars’ atmosphere is very poor because the planet lacks a magnetic field.
| A．covers | B．holds | C．possesses | D．contains |
__________ with such a difficult problem, he decided to ask for some good advice from his colleagues.
| A．Having faced | B．Face |
| C．Faced | D．To have faced |
The leader came into the room, __________ by his two assistants.
| A．following | B．follow | C．followed | D．to follow |
__________ by the heavy rain, the area was flooded seriously.
| A．Stricken | B．Striking |
| C．To strike | D．To be stricken |
The how-to book can be of help to __________ wants to do the job.
| A．who | B．whomever |
| C．no matter who | D．whoever |
The plane crashed in a flash, __________ into pieces.
| A．breaking | B．to break |
| C．to be breaking | D．broke |