Once ____________ , a plan should be carried out.
If one of the computers ___, the whole networks would be unable to work.
After the fire ___ in the shop, Tom ___ the manager.
Thousands of foreigners were ___ to the Shanghai World Expo the day it opened.
In communication, a smile is usually ___ strong sign of a friendly and ___ open attitude.
I remembered ___ the door before I left the office, but forgot to turn off the lights.