1. He touched me on the shoulder.

2. He hit me on the head.
3. He beat me on the back.

4. He looked me in the face.
5. He looked me in the eyes.
6. He looked me in the mouth.

7. He took me by the hand.
8. He caught me by the leg.
9. He grasped me by the neck.
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Are they all grammatical?

All are fine except for #6. I've never heard that one before!

Yes, all of the sentences provided are grammatically correct. They follow the basic sentence structure of subject-verb-object. However, in terms of usage, some of the phrases may sound more natural or commonly used than others. Here's a breakdown of each sentence:

1. "He touched me on the shoulder." - This sentence is grammatically correct and commonly used. It means that someone made physical contact with you by touching your shoulder.
2. "He hit me on the head." - This sentence is grammatically correct, but it suggests a more forceful action than simply touching. It implies that someone struck you, causing physical impact on your head.
3. "He beat me on the back." - This sentence is grammatically correct, but it implies a repetitive or forceful action. It suggests that someone repeatedly hit you on the back with significant force.

4. "He looked me in the face." - This sentence is grammatically correct and often used to indicate direct eye contact. It means that someone made eye contact with you while looking directly at your face.
5. "He looked me in the eyes." - This sentence is grammatically correct and commonly used. It means that someone looked directly into your eyes while making eye contact.
6. "He looked me in the mouth." - This sentence is grammatically correct but less commonly used. It suggests that someone focused their attention on your mouth while observing you.

7. "He took me by the hand." - This sentence is grammatically correct and widely used. It means that someone held or grabbed your hand.
8. "He caught me by the leg." - This sentence is grammatically correct, but it implies a sudden or unexpected action. It suggests that someone grabbed or grabbed hold of your leg.
9. "He grasped me by the neck." - This sentence is grammatically correct and commonly used. It indicates that someone firmly held or grasped your neck, usually with force or intensity.