Die Blumen im Flur sind schon fast verwelkt, deshalb stelle ich sie lieber nach draußen.

im is the contraction of in dem.

So:

• in dem Flur → im Flur

This is very common in German. Here it means in the hallway.

It also tells you the case: dem is dative, which fits because the flowers are located in the hallway, not moving into it.

Because German uses different cases after some prepositions depending on whether you mean:

• location → dative
• direction/movement toward somewhere → accusative

Here, im Flur describes where the flowers are:

• Die Blumen im Flur = the flowers in the hallway

If you were talking about movement into the hallway, you would use accusative:

• Ich stelle die Blumen in den Flur. = I put the flowers into the hallway.

Because die Blumen is the noun first mentioned, and sie refers back to it.

In this sentence:

• Die Blumen = the subject of the first clause
• sie = the direct object in the second clause

So:

• Die Blumen ... sind ... = The flowers are ...
• ich stelle sie ... = I put them ...

A useful thing to remember: sie can mean several things in German, including:

• she
• they
• them
• formal you

Here, context makes it clear that it means them.

Because verwelken is an intransitive verb, and verbs of change of state often go with sein in German.

So verwelkt here is connected with sind and describes the state/result:

• Die Blumen sind verwelkt. = The flowers have wilted / are wilted.

This is one of those places where German and English do not match word-for-word. English often prefers have wilted, but German commonly uses sein with this kind of verb.

Also, in real usage, sind verwelkt can feel like either:

• a completed change: have wilted
• a resulting state: are wilted

The sentence is focusing on their condition now.

schon fast means something like:

• already almost
• already nearly

It shows that the flowers are close to being completely wilted.

Breaking it down:

• schon = already
• fast = almost / nearly

So sind schon fast verwelkt means they are not necessarily fully wilted yet, but they are very close.

Because this sentence contains two main clauses:

1. Die Blumen im Flur sind schon fast verwelkt
2. deshalb stelle ich sie lieber nach draußen

deshalb means therefore / that’s why, but it is not a subordinating conjunction like weil. It is an adverb connecting one main clause to another.

That is why the second part still has normal main-clause word order, and the comma separates the two clauses.

Because German main clauses follow the verb-second rule.

That means the finite verb must come in the second position. If deshalb is placed first, then the verb has to come next:

• Deshalb stelle ich sie lieber nach draußen.

Structure:

• Position 1: deshalb
• Position 2: stelle
• then: ich

This is a very common pattern in German.

You could also say:

• Ich stelle sie deshalb lieber nach draußen.

That is also correct, but the emphasis is slightly different.

Here lieber means rather or preferably.

So:

• ich stelle sie lieber nach draußen = I’d rather put them outside / I prefer to put them outside

It suggests that, given the situation, putting them outside seems like the better choice.

This is related to:

• gern = gladly / like doing
• lieber = rather / prefer
• am liebsten = most preferably / like best

For example:

• Ich trinke gern Tee. = I like drinking tea.
• Ich trinke lieber Tee als Kaffee. = I prefer tea to coffee.

German often chooses different verbs depending on the position of the object.

stellen usually means to put/set something in an upright position or place it somewhere.

That fits well with flowers, especially if they are:

• in a vase
• in a pot
• standing upright in some way

Compare:

• stellen = put standing/upright
• legen = lay something down flat
• setzen = set someone/something down, often with people/animals or in more specific contexts

So stelle ich sie nach draußen sounds natural for flowers being moved outside.

Because nach draußen expresses movement toward the outside, while draußen by itself expresses location outside.

So:

• nach draußen = outside, to the outside
• draußen = outside, outdoors

In this sentence, the speaker is moving the flowers:

• ich stelle sie nach draußen = I put them outside

If you said:

• Die Blumen stehen draußen

that would mean the flowers are already outside.

So the difference is basically:

• where to? → nach draußen
• where? → draußen