3 Open the brackets using Present Simple or Present Continuous.
What you 1,
(to do) this weekend?
I 2 (to try) something thrilling, I have taken up freediving,
Mm, I haven't heard about it. What kind of activity is it?
It 3
(to be) really exciting, I like it! You take a deep breath and go
down into water without an air tank, just a wetsuit, goggles and monofin.
I 4. (to want) to try this sport.

1. What are you doing this weekend?
2. I am trying something thrilling, I have taken up freediving.
3. It is really exciting, I like it! You take a deep breath and go down into the water without an air tank, just a wetsuit, goggles, and a monofin.
4. I want to try this sport.

Explanation:
To open the brackets using Present Simple or Present Continuous, we need to determine if the action is happening at the moment of speaking (Present Continuous) or if it is a general statement (Present Simple).

1. What are you doing this weekend?
In this case, we are asking about the person's plans for the upcoming weekend. The action is happening in the future, so we use Present Continuous: 'What are you doing' (Present Continuous form of 'to do').

2. I am trying something thrilling, I have taken up freediving.
Here, the person is talking about their current interest in a new activity. The action is happening at the moment of speaking, so we use Present Continuous: 'I am trying' (Present Continuous form of 'to try').

3. It is really exciting, I like it! You take a deep breath and go down into the water without an air tank, just a wetsuit, goggles, and a monofin.
In this sentence, the person is explaining what freediving is like. The action is a general statement and not happening at the moment of speaking, so we use Present Simple: 'It is really exciting' (Present Simple form of 'to be').

4. I want to try this sport.
Here, the person is expressing their desire to try freediving. It is a general statement, so we use Present Simple: 'I want' (Present Simple form of 'to want').

By using the appropriate tenses, we ensure that our statements are clear and accurate in relation to the time frame in which the actions are happening.