"She had a rude awakening this morning."
Translation:Elle a eu un réveil difficile ce matin.
In English, a "rude awakening" usually means a metaphoric "awakening," that is, "upsetting news." But the French sentence here seems to mean literally, she had a hard time waking up and getting out of bed this morning, in which case the English isn't accurate. Anyone else have the same reaction?
It seems you can use it literally in English too, cf some of the examples under sense 2 here https://en.oxforddictionaries.com/definition/rude.
Avoir eu (a eu for the third person elle) is the passé composé form of avoir. If you're asking why the sentence uses passé composé as opposed to imparfait, it's because having a rude awakening is more of an event than a general statement about the past.
It's literally "has had". "She has had a rude awakening this morning." French no longer uses the simple past, so you have to use the passé composé here.