[简答题]Scientists have long assumed that most of the ice that melted was in the Northern hemisphere (半球) during the 30,000-year long ice age.

[简答题]Scientists have long assumed that most of the ice that melted was in the Northern hemisphere (半球) during the 30,000-year long ice age.

[填空题]Most American school students have a long summer vacation. It is usually from June to{{U}} (11) {{/U}}. During this vacation, students often travel or have{{U}} (12) {{/U}}. Some students take some les sons in summer school. Mary is one of them. She also traveled with her family. They visited some{{U}} (13) {{/U}}places near their home in Seattle. Mary’ s friend, Peter, worked at a gas station during the vacation. He sold oil and{{U}} (14) {{/U}}cars. He made some money and saved{{U}} (15) {{/U}}all of it. Peter is going to university next year. He needs money for the tuition.

[单项选择]Scientists have long believed that constructing memories is like playing with neurological toys. Exposed to a barrage of sensations from the outside world, we connect together brain cells to form new patterns of electrical connections that stand for images, smells, touches and sounds.
The most unshakable part of this belief is that the neurons used to build these memory circuits are depletable resource, like petroleum or gold. We are each given a finite number of cells, and the supply gets smaller each year. That is certainly how it feels as memories blur with middle age and it gets harder and harder to learn new things. Maybe it’s time for this notion to be forgotten-or at least radically revised.
In the past two years, a series of confusing experiments has forced scientific researchers to rethink this and other assumptions about how memory works. The perplexing results of these experiments remind scientists how much they have to learn about one of the last great mysteries-h
A. The neurons used to build the memory are a depletable resource.
B. The reason of memory loss as one grows older is that the neurons are worn out with the increase of age.
C. New memories do not need the supply of new neurons in the brain.
D. All of above.

[单项选择]

Network managers have long awaited practical voice-over-IP (VOIP) solutions. VOIP promises ease network management and decreases (1) by converging a company’s telephony and data infrastructures into one network. And a VOIP solution implemented at a company’s head-quarters with far-reaching branch offices can (2) tremendous amounts of money in long distance phone bills, provided that solution delivers POTS-like voice (3) over the Internet.
VOIP gateways are designed to convert voice from the (4) domain to the circuit switched domain. VOIP solutions use a digital signal processor (DSP) to process the voice data, preparing the voice sample for transmission by compressing voice and removing jitter. The VOIP equipment must comply with the (5) H.323 standard defined by the International Telecommunication Union, or ITU.

3（）
A. quality
B. frequency
C. length
D. quantity