Mit dem Daumen drücke ich den Lichtschalter, weil ich die rechte Hand noch nicht gut bewegen kann.

Because mit always takes the dative case in German.

• der Daumen = the thumb
• dative singular becomes dem Daumen

So:

• mit der Hand
• mit dem Finger
• mit dem Daumen

This phrase means with the thumb / using the thumb.

Because den Lichtschalter is the direct object of drücken.

The verb drücken takes an object in the accusative case:

• der Lichtschalter = nominative
• den Lichtschalter = accusative

So in the sentence, the thing being pressed is the light switch, which makes it accusative.

German often puts a different element first when the speaker wants to highlight it.

Here, Mit dem Daumen is placed first for emphasis, probably because the important point is how the person is pressing the switch.

Even when something other than the subject comes first, German still keeps the conjugated verb in second position in a main clause:

• Ich drücke den Lichtschalter mit dem Daumen.
• Mit dem Daumen drücke ich den Lichtschalter.

Both are correct. The second one emphasizes with the thumb.

Because German main clauses follow the V2 rule: the finite verb must be in the second position.

In this sentence, the first position is taken by Mit dem Daumen, so the verb must come next:

• Mit dem Daumen = position 1
• drücke = position 2
• ich comes after that

This is very normal in German word order.

Because weil introduces a subordinate clause, and in subordinate clauses German sends the finite verb to the end.

So:

• main clause: Ich kann die rechte Hand noch nicht gut bewegen.
• subordinate clause after weil: weil ich die rechte Hand noch nicht gut bewegen kann

That final kann is exactly what you expect after weil.

Because this clause contains a modal verb: können.

In a normal main clause:

• Ich kann die rechte Hand bewegen.

But after weil, the clause becomes subordinate, so the verb structure moves to the end:

• weil ich die rechte Hand bewegen kann

The main conjugated verb here is kann, and bewegen stays in the infinitive.

So with modal verbs in subordinate clauses, you often get:

• ... infinitive + modal verb
• here: bewegen kann

Because Hand is a feminine noun: die Hand.

In this sentence it is the object of bewegen, so it is in the accusative case. For feminine nouns, nominative and accusative both use die:

• nominative: die rechte Hand
• accusative: die rechte Hand

The adjective ending -e is correct here because the definite article die already shows the gender and case clearly.

German often uses the definite article with body parts when it is already obvious whose body part is meant.

So:

• ich kann die rechte Hand nicht gut bewegen
• literally: I can’t move the right hand well
• natural meaning: I can’t move my right hand well

Using meine rechte Hand is possible, but it sounds more explicit or emphatic. In many everyday situations, German prefers the article.

Here:

• noch nicht = not yet
• gut = well

So noch nicht gut bewegen kann means something like cannot move well yet.

The order is natural German word order:

• noch nicht usually stays together
• gut describes bewegen

So the sentence means the hand is not yet functioning well, probably implying improvement may come later.

Because the sentence is talking about one specific hand: the right hand.

German uses the singular exactly like English does here:

• die rechte Hand = the right hand

If it were plural, it would mean the right hands, which would not fit the situation.

Yes, absolutely.

That version is also correct and probably feels a bit more neutral to many learners because it starts with the subject:

• Ich drücke den Lichtschalter mit dem Daumen, weil ich die rechte Hand noch nicht gut bewegen kann.

The original sentence:

• Mit dem Daumen drücke ich den Lichtschalter ...

puts more emphasis on with the thumb.

So the difference is mainly focus and style, not basic meaning.

Because in German, drücken is commonly used for pressing buttons, switches, and similar things.

So:

• einen Knopf drücken = to press a button
• den Lichtschalter drücken = to press the light switch

Depending on the type of switch, Germans may also use other verbs in some contexts, but drücken is perfectly natural if the switch is something you press.

Weil means because and gives the reason for the action in the main clause.

Structure:

• main clause: Mit dem Daumen drücke ich den Lichtschalter
• reason clause: weil ich die rechte Hand noch nicht gut bewegen kann

So the sentence is built as:

• action first
• explanation after weil

This is one of the most common ways to join two ideas in German.

It is about ability, not permission.

• ich kann ... bewegen = I can move ...
• here with noch nicht gut: I cannot move it well yet

So können often means to be able to, and that is the meaning in this sentence.