. Mage is rather difficult to make friends with, but her friendship, _____ is truer than any other.
| A．once gained | B．when to gain | C．after gained | D．while gaining |
______the nurses want a pay increase, they want reduced hours as well.
| A．Not do only | B．Do not only | C．Only not do | D．Not only do |
—Who’s that at the door?
—is the milkman.
| A．He | B．It | C．This | D．That |
Exactly______ the potato was introduced into Europe is uncertain, but it was probably around 1565.
| A．whether | B．why | C．when | D．how |
Today there are more airplanesmore people than ever before in the skies.
| A． | carry | B． | carrying | C． | carried | D． | to be carrying |
Unless some extra money________, the theatre will be close.
| A．was found | B．finds | C．is found | D．found |