Most birds find it safe to sleep in the trees, but _____ they have eggs or young chicks, they don’t use a nest.
| A．why | B．how | C．unless | D．where |
All of the flowers now raised here have developed from those _____ in the forest.
| A．once they grew | B．they grew once | C．that once grew | D．once grew |
The modern history of Italy dates from 1860, ______ the country became united.
| A．when | B．if | C．since | D．until |
We will be shown around the city: schools, museums, and some other places, _______ other visitors seldom go.
| A．what | B．which | C．where | D．when |
The old building, behind _______ was a famous church, was _______ we used to work.
| A．that, the place | B．it, the place | C．which, where | D．what, where |
The little time we have together we’ll try _____ wisely.
| A．spending it | B．to spend it | C．to spend | D．spending that |