helping to 3)______________ and save energy.
A: prove security
B: improve
C: improving security
D: improve security
A: prove security
B: improve
C: improving security
D: improve security
举一反三
- The basic economic problem is _______. A: scarcity B: health and medical security C: reduce unemployment D: improve people's income
- ________<br/>means the level for which appropriate additional<br/>protective security measures shall be maintained for a period of time<br/>as a result of heightened risk of a security incident. A: Security level 1 B: Security level 2 C: Security level 3 D: Security level 4
- Frank works as ______. A: a security guard at a university B: a security guard at university C: a security guard at the university D: security guard at a university
- helping to 3)______________ and save energy.
- ________means<br/>the level for which further<br/>specific protective<br/>security measures shall be maintained for a limited period of time<br/>when a security incident is probable or imminent, although it may not<br/>be possible to identify the specific target. A: Security level 1 B: Security level 2 C: Security level 3 D: Security level 4