[填空题]The Internet can be used to distribute large amounts of information anywhere in the world __________________ (以最低成本).

[填空题]A large percentage of severe depression can be relieved or treated but in reality, most of them are not seriously taken.

[单项选择]　　That large regions of the galaxy can be influenced by the formation of massive stars in a few localized regions requires that star formation somehow be coordinated over long periods of time. The process commences with a single O-type star or a cluster of such stars in a giant molecular cloud, around which stellar radiation, winds and explosions carve a modest cavity from of the surrounding interstellar medium, concomitantly destroying the progenitor cloud. Perchance this disturbance triggers star formation in a nearby cloud, and so on, until the interstellar medium in this corner of the galaxy resembles Swiss cheese, composed of what theorists have recently begun to refer to as bubbles, or superbubbles, one of the most exciting discoveries in astrophysics in years. Within a hot bubble, the sun has revealed itself in x-rays emitted by highly ionized trace ions such as oxygen and at some point in the process of its formation, nearby bubbles commence to overlap, coalescing into a superb
A. The gravitational attraction of supernovas adjacent to the region of the chimney’’ s formation
B. The effect of entropy on the relative abundance of hot interior gas within the superbubble
C. A chemical reaction involving ionized trace ions at the heart of the superbubble
D. A tendency toward coalescence in the gases that contribute to the formation of the superbubble
E. A natural buoyancy of the superbubble, which causes the chimney to stretch and become a gaseous conduit