1. The work is too difficult to do.

2. The work is so difficult that I cannot do it.

(Does #1 mean #2? Are both the same?)

3. Mother Teresa......

(Why do you use 'Mother' before Teresa, the famous nun who passed away?)

4. I hope to be a scientise.
5. I hope that I will be a scientist.

(Can #4 be changed into #5? Are both the same?)

6. I am so glad to see you.
7. I am so glad that I see you.
(Are both the same? Are they interchangable?

8. He has two sons wearing white shirts.

9. He has two sons who are wearing white shirts.

10. He has two sons who wear white shirts.

(Are #8,9,and 10 the same?)

11. Do you know why to go abroad?
12. Do you know why you should go abroad?

Does #12 mean #11? Can we say like (#11?)

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Would you like to answer my questions?

1. The work is too difficult to do.

2. The work is so difficult that I cannot do it.

(Does #1 mean #2? Are both the same?)
Yes, they are different ways to say the same thing.

3. Mother Teresa......

(Why do you use 'Mother' before Teresa, the famous nun who passed away?)
"Mother" is a term used when speaking to or about a nun who has risen to certain status in the religious organization she's in. http://en.wikipedia.org/wiki/Mother_Teresa

4. I hope to be a scientise.
5. I hope that I will be a scientist.

(Can #4 be changed into #5? Are both the same?)
Both are the same; be sure to correct the spelling of "scientist" in #4.

6. I am so glad to see you.
7. I am so glad that I see you.
(Are both the same? Are they interchangable?
The first is fine and is what we normally say. The second is not used unless you're playing some kind of hide-and-seek game!

8. He has two sons wearing white shirts.

9. He has two sons who are wearing white shirts.

10. He has two sons who wear white shirts.

(Are #8,9,and 10 the same?)
Yes, they are basically the same; 8 and 9 are identical in meaning; 10 implies that they wear white shirts every day, no alternatives!

11. Do you know why to go abroad?
12. Do you know why you should go abroad?

Does #12 mean #11? Can we say like (#11?)
#12 is the correct one; #11 is not used.

Yes, I'd be happy to answer your questions!

1. In the context of difficulty, "The work is too difficult to do" implies that the level of difficulty is beyond a person's capability or capacity to complete it. On the other hand, "The work is so difficult that I cannot do it" suggests that the work is extremely challenging to the point of being impossible. While both sentences convey a similar idea, the second sentence emphasizes the inability to complete the work due to its high level of difficulty. So, they are not exactly the same, but they convey a similar meaning.

2. Using "Mother" before "Teresa" is a common way to address or refer to a prominent figure, especially when there may be multiple individuals with the same last name. Adding "Mother" in front of "Teresa" helps to specifically identify and honor the famous nun, as there are other people with the last name "Teresa."

3. Yes, "I hope to be a scientist" can be changed to "I hope that I will be a scientist." Both sentences express a similar idea, focusing on the desire and aspiration to become a scientist in the future.

4. "I am so glad to see you" and "I am so glad that I see you" are similar in meaning but have slightly different structures. The first sentence "I am so glad to see you" expresses happiness upon the act of seeing the person. The second sentence "I am so glad that I see you" implies continued joy in seeing the person. While they convey a similar sentiment, the first sentence emphasizes the initial moment of seeing, while the second sentence implies an ongoing feeling of happiness by regularly seeing the person. So, they are not entirely interchangeable, but the difference is subtle.

5. "He has two sons wearing white shirts" refers to his sons currently wearing white shirts.
6. "He has two sons who are wearing white shirts" implies that his sons are currently wearing white shirts.
7. "He has two sons who wear white shirts" indicates that his sons have a habit or tendency to wear white shirts.

While all three sentences convey the idea of his sons wearing white shirts, sentences 6 and 7 add additional information about their current state or habitual behavior. Sentence 8 is the simplest and does not specify any additional details beyond the current situation.

8. "Do you know why to go abroad?" is not grammatically correct. The correct sentence would be "Do you know why you should go abroad?" The second sentence, "Do you know why you should go abroad?" implies that the person being asked has some knowledge or information about the reasons to go abroad and the speaker is inquiring about that knowledge. It suggests that there are specific reasons or advantages for going abroad. So, sentence 12 conveys a clearer idea compared to sentence 11.

I hope these explanations clarified your questions! Let me know if there is anything else I can assist you with.