Mein Brückenjahr: preposition 'bei', 'beim' and 'am' with nominalised verbs

'Bei' means 'at' or 'with' and takes the dative. When used with masculine or neuter nouns, 'bei dem' becomes 'beim'. To mean ‘whilst’ or ‘in the process of’ doing something, use 'beim' before a nominalised infinitive, e.g., ‘beim Lesen’. Use 'am' as an alternative to 'beim' to mean ‘in the process of’, but only when a single activity is being done. The use of 'beim' or 'am' plus the nominalised verb indicates the activity is, or was, ongoing or unfinished. In conversation, develop answers by adding opinions and reasons, varying the subject, and adding different time frames.