10."extraordinary,extra-official,extracurricular,extra-professional,extra-solar"andsomeotherwordscontainthesameaffix“extra”whichmeans____________.

28.Mr Black is an ____ in the army，not an ____ in the government. You can not easily find him in his ____. A: official；officer；office B: officer；office；official C: official；official；official D: officer；official；office

You have to pay a(n)premium for express delivery. A: extra charge B: extra price C: extra tip D: extra bonus

When exchange name cards, usually ,（ ）official give theirs to（ ）official .

When exchange name cards, usually ,（ ）people or（ ） official give theirs to older people or higher official .

If demand is price elastic and price decreases, then A: the extra revenue from the extra units sold is exactly offset by the loss in revenue due to the lower price B: more information is necessary to determine what happens to total revenue C: the extra revenue from the extra units sold is less than the loss in revenue from the lower price D: the extra revenue from the extra units sold exceeds the loss in revenue from the lower price

The official languages of Singapore are __________.

________ is the official name of Britain.

.The official languages of Canada are ( ) and ( ).

Providing extra information___________________________