<span>A system and method for manipulating virtual objects in a virtual environment, for drawing curves and ribbons in the virtual environment, and for selecting and executing commands for creating, deleting, moving, changing, and resizing virtual objects in the virtual environment using intuitive hand gestures and motions.</span>
If the verb in the independent clause is in the present tense, the tense that the verb in the indirect quotation should be is <span>remain in its original tense.
</span>You don't have to shift tenses because it is present in the independent one.
For example:
He says: "I need to wash my hair."
He says that he needs to wash his hair.
You wouldn't say - he says that he needed to wash his hair.
<span>Speak quickly so not to bore your audience.</span>
Answer:
1) I go swimming once a week to relieve stress.
2) Took
3) So
4)Study
5) older
6)larger
7) ?
8)was
9) those
10)when