Expressing Time, Place and Cause

You have used when and because to join ideas. When tells a time. Before means earlier than; after means later than. 'Before I painted, I covered the table.' 'After the paint dried, I hung the picture.' While can show actions happening together: 'I listened while I painted.'

A noun names a person, place or thing. A noun group can have several words, like 'the heavy rain'. Prepositions go with noun groups. During the game means within the game's time. Before lunch means earlier than lunch; after lunch means later. In the hall tells where. Because of the rain gives a cause.

Because gives a reason: 'I wore boots because the path was muddy.' Verbs tell actions or states: wore tells an action; was tells a state. Because of takes a noun group: 'I wore boots because of the mud.' The mud names a thing, with no verb. Move the whole because part first: 'Because the path was muddy, I wore boots.' Put a comma after this opening part.

Then and next show what follows. They do not say that it follows at once. Soon means after a short time. Finally can mark the last event in a story. These words can appear in a new sentence. 'The timer rang. Soon, I took out the cake.' The full stop keeps these as two sentences.

Because introduces a reason. So can introduce its result: 'The room was dark, so I switched on a lamp.' Therefore can also show a result: 'The room was dark. Therefore, I switched on a lamp.' Here, therefore begins the second sentence. It does not join the sentences into one.