强调句通常用的句式：it is + 被强调的部分 + that + 句子的其余成分。强调部分指人的时候，用who 或者that; 指物的时候用that。
例1：
It is from the sun that we get light and heat.
被强调的部分(物)
例2：
It was Sam who knocked down that old man and fled.
被强调的部分(人)
注意：如何判断强调句式?
把一个句子中的it is …that/who这个部分去掉，如果剩余的句子仍然是完整的，那么这个句式就是一个强调句。反之则有可能是其他从句。
例如：
It is exciting that we succeeded in launching the satellite.
这个句子虽然也有it is ….that 的结构，但只要把这个结构去掉，就可以发现：剩下的内容不能构成完整的句子。所以这不是一个强调句。在这里It is…that 是不能随便去掉的，因为这里it 是形式主语。
翻译示例：
例：______________ (直到他详细研究)that the first of the vitamins was identified.
1. 所译部分为句子的主干，需要强调句型，表达方式为it is not until...that
2. 从句为过去时，所以主句中也应该是过去时
3. “详细地”表达方式应该是in detail。
答案：It was not until he investigated in detail
实战演练：
1. It was not until 1920 __________ regular radio broadcasts began.
A. while B. which C. that D. since
2. She said she would go and she __________ go.
A. didn’t B. did C. really D. would
3. Why was __________ that the old woman was sent to prison?
A. he B. it C. when D. what
4. It is __________ any wonder that his friend doesn’t like watching television much.
A. no B. such C. nearly D. hardly
5. It was the boy__________ had been in prison __________ stole the money.
A. who, where B. that, how C. who, that D. that, which
6. It was the training __________ he had as a young man __________ made him such a good engineer.
A. what; that B. that; what C. that; which D. which; that
7. — Were all three people in the car injured in the accident?
— No, __________ only the two passengers who got hurt.
A. there were B. it had C. there had D. it was
8. __________ in 1943__________ the harmful smog made its appearance in Los Angeles.
A. Only… that B. It was… then C. That it was… when D. It was… that
9. __________ the 1500's __________ the first European explored the coast of California.
A. It was until……then B. It was not until … when
C. It is until……that D. It was not until……that
10. It was only with the help of the local guide __________.
A. was the mountain climber rescued B. that the mountain climber was rescued
C. when the mountain climber was rescued D. then the mountain climber was rescued
答案及解析：
1. C 2. B 3. B 4. D 5. C 6. D 7. D 8. D 9. D 10. B
1. 本题考查的是强调句式。强调句式由“it is/was + 被强调成分+that/who…”构成。此题强调的是时间。
2. 在谓语动词前加do表示对动作的强调。and连接两个并列谓语，其形式应一致，故用过去时态。
3. 此题考查的是强调句的特殊疑问句形式。it在此作为形式主语，真正的主语是that从句。
4. 此句是一个强调句。根据题意“他的朋友不怎么喜欢看电视”可知这并没有什么可奇怪的，故排除B和C。no后直接加名词相当于not any +名词，可排除A。故选D。
5. 此题考查的强调句中含有一个定语从句。Who引导的定语从句修饰被强调部分the boy，that引导的从句构成强调句中的真正的主语。当被强调部分是人时，可以用that和who来引导从句。
6. 此题考查的强调句型中包含一个定语从句。Which引导的定语从句，修饰被强调部分the training，that从句构成强调句中的真正主语。
7. 本题考查的是强调句式。强调句式由“it was + 被强调成分+ who…”构成。
8. 本题考查的是强调句式。强调句式由“it was + 被强调成分+that…”构成。本句强调的是时间。
9. 本题考查的是强调句式。强调句式由“it was + 被强调成分+that…”构成。本句强调的是时间。not until…意为“直到……才”。
10. 本题考查的是强调句式。强调句式由“it was + 被强调成分+that…”构成。从句的语序仍然用陈述语序。
From:https://www.zgghmh.com/CET-4/20000372.asp