1. But the chances are against it, and there is a virtual limit on how long we can hope to remain alive, however lucky and robust we are.
    但这种可能性很小。不管我们多么幸运，多么健壮，我们所希望的长寿实际上是有限度的。

2. But other suns, stars as the astronomers call them, are bound to have planets like our own, and as the number of stars in the universe is so vast, this possibility becomes virtual certainty.
    但是，其他的太阳，既天文学家所说的恒星，肯定会有像我们地球一样的行星。因为宇宙中恒星的数目极其庞大，所以存在着产生生命星球的这种可能性是肯定无疑的。

3. While regular schools still exist, the virtual classroom plays an important role in today's learning community.
    虽然常规的学校依然存在，但虚拟课堂在今天的教学领域中起着重要的作用。

4. He is in a state of virtual slavery.
    他实际上处于一种被奴役的状态。

5. Pessimists believe further population growth will eventually cause a virtual collapse of public services in many cities.
    悲观主义者认为，人口的进一步增长最终将使许多城市的公共设施崩溃，

6. Providing meaningful and quality input into the virtual classroom is an essential part of online learning.
    要花时间斟酌并仔细作答，

7. I soon got access to the necessary equipment, learned the technology from a friend and participated in the virtual classroom 5 to 7 days a week.
    我很快配齐了必要的设备并跟一个朋友学会了电脑操作技术，于是我每周用５到７天在网上的虚拟课堂里学习英语。

8. In the virtual classroom nearly all communication is written, so it is critical that students feel comfortable expressing themselves in writing.
    虚拟课堂的交流几乎都是书面形式。因而很重要的一点是要让学生感到书面交流并不别扭。