Efficient air service has been made available through modern technology.A．AffluentB．Modern

A large quantity of air－conditioners has been sold since the temperature is high.（英译中)

Postal services generally are not as efficient in this regard. {A; B; C}A. 通常说来，

According to the passage, Redbox______.A．has a streaming－video service nowB．has been resea

______relatively costly, the engine is highly efficient and needs servicing infrequently.A

Cuts in funding have meant that equipment has been kept in service long after it______ hav

Which of the following is NOT true？A．Singapore has always been a highly efficient country