Learn Swedish: Jag har nyligen läst en fantastisk bok. - I have recently read a fantastic book.

The sentence is in the present perfect tense ("have read"), which in Swedish uses har followed by a special verb form called the supinum (supine). Because läsa (to read) is a Group 2 verb, you form its supinum by adding -t to the verb stem, giving us läst.

If we used a Group 1 verb here instead, how would the ending after har be different?

While Group 2 verbs like läsa end in -t in their supinum form, Group 1 verbs end in -at. For example, if you swapped in the Group 1 verb börja (to start), the sentence would be Jag har nyligen börjat.

Why does nyligen go between har and läst?

In a standard main clause, sentence adverbs like nyligen (recently) are placed right after the first conjugated verb (har). The adverb sits between the helper verb and the main verb, which luckily matches the English word order here ("have recently read").

Why isn't there an -a or -t at the end of fantastisk?