serve as ____ of the Lambert Warner Christmas Ball for the last two years;

The ozone layer plays as great a role in the stability of spaceship Earth as ______ the wa

There are some rooms in the beach house, ______served as a kitchen.A．the smaller of thatB．

The birthday of the ______ is sometimes served as the National Day of Britain.A．head of th

Unemployment insurance serves as the economys automatic stabilizer in that it______.A．prov

The function of the first paragraph is to______.A．serve as a prelude to the key event in t

______lie（s)between the boundary of Canada and the U. S. and serve（s)as the boundary betwe