--Why do you look so upset, Linda?--There are so many troublesome problems____.
They ________have arrived at lunchtime but their flight was delayed.
—Happy birthday! —Thank you! It's the best present I________ for.
We ________ have bought so much food now that Suzie won't be with us for dinner.
—Why are your eyes so red? You ________ have slept well last night. —Yeah, I stayed up late writing a report.
Harry is feeling uncomfortable.He ________ too much at the party last night.