Open the brackets. Use the Present Perfect Simple Tense or the Present Perfect Continuous Tense. How long you (know) Kate?

To answer the question "How long have you known Kate?", we will use the Present Perfect Simple Tense because we are interested in the duration of time up until the present moment.

Step 1: Understand the form of the tense
The Present Perfect Simple Tense is formed by using the auxiliary verb "have" or "has" followed by the past participle form of the main verb.

Step 2: Determine the subject
In this sentence, the subject is "you" which means the person being addressed.

Step 3: Identify the correct form of the verb "know"
The base form of the verb "know" is "know." However, in the Present Perfect Simple Tense, the past participle form of "know" is "known." We will use this form in our sentence.

Step 4: Construct the sentence
Now that we have all the information, we can construct the sentence: "How long have you known Kate?"

Step 5: Provide an explanation
In this sentence, we are asking for the duration of time that the person has known Kate. By using the Present Perfect Simple Tense, we are emphasizing that the person's knowledge of Kate started in the past, but it is still relevant in the present. We use this tense when we want to connect the past and the present.

The sentence could be answered with a specific duration of time, such as "I have known Kate for five years." This means that the person has had knowledge of Kate for a period of five years and they still know her at present.

Alternatively, the sentence could be answered with a non-specific duration of time, such as "I have known Kate for a while." This means that the person has some knowledge of Kate for an undefined period and they still know her at present.

Overall, the Present Perfect Simple Tense allows us to indicate a connection between the past and the present when discussing duration or experiences that started in the past and are still relevant now.