Too/either, so am I/neither am I

Let's dive into the detailed grammar explanation of the concepts of "too/either" and "so am I/neither am I" in different verb tenses.

1. TOO and EITHER

"Too" and "either" are used to show agreement or inclusion in a positive statement.

"Too" is used in affirmative sentences

"Either" is used in negative sentences

  - They are placed at the end of a sentence, after the verb or auxiliary verb.

Examples:

Affirmative: "I love chocolate, and she does too."

     (The speaker loves chocolate, and the other person also loves chocolate.)

Negative: "I don't like spicy food, and he doesn't either."

     (The speaker doesn't like spicy food, and the other person also doesn't like spicy food.)

2. SO AM I and NEITHER AM I

"So am I" and "neither am I" are used to show agreement or inclusion in a positive or negative statement, respectively.

   - They are used when agreeing with a positive or negative statement about oneself.

   - They are used to indicate that the speaker has the same opinion, feeling, or experience as the person they are responding to.

Examples:

   - Positive: "I am a teacher, and he is too." 

     Response: "So am I." (The speaker agrees that they also love playing tennis.)

   - Negative: "They are not happy, and they aren’t either."

     Response: "Neither am I." (The speaker agrees that they also don't like spicy food.)

Now, let's look at how these concepts work with different verb tenses:

1. Present Simple:

   - Affirmative: "I play soccer, and he does too."

   - Negative: "I don't eat meat, and she doesn't either."

   - Positive response: "So do I."

   - Negative response: "Neither do I."

2. Present Continuous:

   - Affirmative: "I am studying, and they are too."

   - Negative: "I'm not feeling well, and he isn't either."

   - Positive response: "So am I."

   - Negative response: "Neither am I."

3. Present Perfect:

   - Affirmative: "I have visited Paris, and she has too."

   - Negative: "I haven't seen that movie, and he hasn't either."

   - Positive response: "So have I."

   - Negative response: "Neither have I."

4. Past Simple:

   - Affirmative: "I went to the party, and they did too."

   - Negative: "I didn't finish the project, and she didn't either."

   - Positive response: "So did I."

   - Negative response: "Neither did I."

5. Past Continuous:

   - Affirmative: "I was studying, and he was too."

   - Negative: "I wasn't paying attention, and she wasn't either."

   - Positive response: "So was I."

   - Negative response: "Neither was I."

Remember to match the verb form (present simple, present continuous, etc.) when using "too/either" and "so am I/neither am I" to maintain grammatical consistency.