Learn Hardcore Portuguese (Portugal): A corda molhada pode fazer-te escorregar, por isso agarra-te com força. - The wet rope can make you slip, so hold on tight.

Because it refers to corda, which is a feminine noun in European Portuguese. Adjectives must agree in gender and number with the nouns they modify, so molhada (feminine singular) matches corda.

Why is te attached to fazer as fazer-te instead of placed before the verb?

In European Portuguese, when you have an infinitive (here fazer) combined with a clitic pronoun, you normally use enclisis: you attach the pronoun after the verb with a hyphen. So fazer + te → fazer-te.

Why is escorregar in the infinitive rather than a conjugated form?

After verbs of causing or permitting (like fazer, deixar, mandar), the second action is expressed by an infinitive:
• pode fazer-te escorregar = “it can make you slip.”

What does por isso mean and how is it different from então?

Por isso literally means “because of that,” so it’s used like “therefore” or “so.” It emphasises a direct consequence of the previous clause. Então can also mean “so/then,” but is more colloquial and can introduce questions or sequences, not always signalling strict cause → effect.

Why is the command agarra-te used here, and what person is it?

Agarra-te is the affirmative imperative of agarrar for the second-person singular (tu). In European Portuguese imperatives, you attach the clitic pronoun enclitically: agarra + te → agarra-te (“grab yourself”).

Could you say agarra com força instead of agarra-te com força?

Yes. Agarra com força (“grab with strength” or “hold tightly”) is also natural. You drop te when it’s clear who the action targets. If you want to stress “hold yourself,” keep agarra-te, but agarra com força is perfectly idiomatic.

Why is it com força and not fortemente ("strongly")?

Com força (“with force/strength”) is the more idiomatic way to say “hard” or “tightly” in commands. Fortemente exists (“strongly”), but it’s more formal and less common in spoken imperatives about grip.