1. Tom is angry at her.

1-2. Tom is angry with her.
(Which one is correct?)

2. He is wearing a white shirt.
2-2. He is wearing a dress shirt.
2-3 He is wearing an under shirt.
(Which one is correct? Do #2 and #2-2 have the same meaning? Why do we use 'dress' for a man's clothing?)

3. Do you have any plans for the weekend?
3-2. Do you have any plan for the weekend?
(Which one is correct? Are both OK? Do we have to use a singular noun or a plural noun?)

4. Who protec us from them?
4-2. Who protects us from them?
(Which one is correct? Which one is grammatically correct?)

5. He's got a cold and he coughs a lot.
5-2. He's got cold and he coughed a lot.
(Which one is correct?)

6. Do you have a toothache? Why don't you go to the dentist?

6-2. Do you have a toothache? Why don't you go to the dentist's office?

6-3. Do you have a toothache? Why don't you go to the dentist's?

6-4. Do you have a toothache? Why don't you go to see a dentist?

(Which one is right?)

#1 - I prefer the second one although I've heard both.

#2 - All three are correct, depending on what you mean. A white shirt is just that, and it could be worn to the office or wherever. A dress shirt means a shirt to be worn with a suit or tuxedo.

#3 - Both are OK, but the first one is more commonly used.

#4 - The second one is correct.

#5 - It's better to say, "He has a cold, and he coughs a lot." Or "He has a cold and coughs a lot."

#6 - The first one is the best; the fourth one is not bad if you delete "to."

1. Both "Tom is angry at her" and "Tom is angry with her" are correct, but they have slightly different meanings. "Tom is angry at her" implies that Tom is directing his anger towards her, while "Tom is angry with her" suggests that Tom and her are both experiencing anger together.

2. "He is wearing a white shirt" and "He is wearing a dress shirt" are both correct, but they refer to different types of shirts. A white shirt is a general term for any shirt that is white in color, while a dress shirt specifically refers to a formal shirt that is typically worn with a suit.

3. Both "Do you have any plans for the weekend?" and "Do you have any plan for the weekend?" are grammatically correct, but they have slightly different meanings. "Do you have any plans for the weekend?" suggests that the person is asking if the other person has multiple plans or activities lined up for the weekend. "Do you have any plan for the weekend?" suggests that the person is asking if the other person has a specific plan or activity in mind for the weekend.

4. "Who protects us from them?" is the correct sentence. In this sentence, the verb "protects" agrees with the singular subject "Who." The sentence is grammatically correct.

5. "He's got a cold and he coughs a lot" is the correct sentence. The verb "coughs" matches the subject "he" in the present tense. "He's got cold and he coughed a lot" is not grammatically correct because the verb tense "coughed" is in the past tense, while the rest of the sentence is in the present tense.

6. All four options are grammatically correct, but they have slightly different meanings:

- "Do you have a toothache? Why don't you go to the dentist's office?" suggests that the person should go to the physical location where the dentist works, such as a dental clinic.
- "Do you have a toothache? Why don't you go to the dentist's?" suggests that the person should go to the dentist's general location, without specifying the office. This could mean either the dentist's office or another practice where the dentist works.
- "Do you have a toothache? Why don't you go to see a dentist?" suggests that the person should go see any dentist, without specifying a particular location or office.

Ultimately, the best option depends on the specific context and what the speaker wants to convey.