Questions & Answers about Kannst du die schwere Tasche heben?
Because this is a yes/no question in German. In main-clause yes/no questions, the conjugated verb usually comes first.
- Kannst du die schwere Tasche heben? = Can you lift the heavy bag?
- Statement version: Du kannst die schwere Tasche heben. = You can lift the heavy bag.
So the first-position verb is a big clue that this is a question.
Kannst is the du form of the verb können, which means can / to be able to.
Here is the present tense:
- ich kann = I can
- du kannst = you can
- er/sie/es kann = he/she/it can
- wir können = we can
- ihr könnt = you all can
- sie/Sie können = they / you (formal) can
The -st ending marks the verb for du.