Glad to see you back. How long in Russia?
| A．did you stay | B．have you stayed | C．were you staying | D．have you been staying |
exit
| A．exercise | B．exactly | C．exhibition | D．experiment |
—The hall___ for international conferences is of great importance．
—I see, and we are sure to complete it on time．
| A．built | B．to be built |
| C．having been built | D．building |
Since Tom ___downloaded a virus into his computer, he can not open the file now．
| A．readily | B．horribly | C．accidentally | D．irregularly |
Seeing that the drowning child was struggling in the icy water, the soldier dived into the river without hesitation, ___ his own safety．
| A．regardless of | B．in terms of | C．in face of | D．because of |
If you just spend your time___ gains and losses, maybe you'll get nothing in the end．
| A．checking | B．weighing | C．balancing | D．examining |