Our research has focused on a drug which is so _____ as to be able to change brain chemistry.
| A．powerful | B．influential | C．monstrous | D．vigorous |
. Probability is the mathematical study of the _____ of an event's occurrence.
| A．desire | B．likelihood | C．result | D．effect |
. New mineral resources may be discovered during the forthcoming Antarctic _____.
| A．excursion | B．execution | C．extraction | D．expedition |
They have been waiting for many hours to see the singer, but the airplane must have been _____.
| A．behind the times | B．behind schedule |
| C．ahead of time | D．in no time |
Today, housework has been made much easier by electrical _____.
| A．facilities | B．appliances | C．instruments | D．equipment |
Pack the cake in a strong box, or it might get _____ in the post.
| A．splashed | B．spilt | C．crushed | D．crashed |