According to the passage, by 2007, before its construction, a new building will have to ______.

A．Attending the party.
B．Visiting some friends.
C．Studying for an exam.
D．Taking an exam.

A．The possible existence of life on other planets.
B．Methods for building powerful new telescopes.
C．A technical problem that astronomers can’t solve.
D．The discovery of planets orbiting distant stars.