yet

当 yet 指“现在还”(now, at this moment)、“到目前为止还”(up to now, up to the present time, up to this moment, up to the moment of speaking, so far)、“至当时还”(up to then)时，它只能用在疑问句和否定句中。但是，在你引用的句子里，yet 并不具有上述含义，而是接近 still 的含义(还，仍然)。具有这种含义的 yet 是可以用在肯定句的。例如：

1. Much yet remains to be done. (COD) 还有许多事情需要做。

2. There are three days yet to go until my vacation. (MD) 离我的假期还有三天时间。

3. I have a few more words to say yet. 我还有几句话要说。

4. I can see him yet. (CGEL) 我还能看到他。

5. There's plenty of time yet. 还有许多时间。

一般说来,yet大都用在否定句和疑问句中。但是,yet也可用在含有情态动词的肯定结构中。这时,yet的意义与still同义,而且表示将来时间(at a future time):

1. I have yet to find out what he wants. (CGEL) 我还必须弄清他需要什么。

2. Who'll be appointed? ——It's yet to be decided. (LEG) 谁会得到任命呢？——这还有待决定。

3. The plan may even yet succeed. (LDAE) 这计划还是有可能成功的。

4. The enemy may yet win if we relax our efforts. (ALD) 如果我们松懈下来,敌人还是有可能取胜的。

5. We may yet hear from him. (ELD) 我们还是有可能收到他的信的。

6. The figures may yet be revised again. (EED) 这些数字还是可能重新修改的。

7. I have yet to hear the story. (LDCE) 我还是得听听这个故事。

8. I have yet to meet him. (CGEL) 我还是得见见他。

9. The first snowdrops are yet to appear. (EED) 头几场雪还是会来临的。

10. The most severe weather is yet/still to come. (CGEL) 最恶劣的天气还是会来临的。

在英国英语中，在含有 just, already, yet, ever, never 等副词的句子要使用现在完成时。

1. I haven't made up my mind yet. 我还没有下决心。

2. He may have plans, but he hasn't yet spoken to me about them. 他可能已有计划，但他还没有向我谈过。

3. I don't know. I haven't yet heard from him. (Dan Brown, The Da Vinci Code) 不知道,我还没收到他的回信呢! (《达·芬奇密码》)

但是,在美国英语中,有时候在这种情况下,也使用一般过去时(见 already $^{1}$ ):

1. I didn't call Bobby yet. (PEU) 我还没有给博比打电话。

2. I just met an old friend. (OGEG) 我刚才见到一个老朋友。

3. Did you eat already? (PEU) 你已经吃饭了吗?

4. I never had a passport. (OGEG) 我从来就没有护照。

见 already/yet。

$\mathbf{y}\mathbf{e}\mathbf{t}^{6}$

though ... yet 见 though...yet