Present Perfect or Past Simple?

Alex ___________ (go) to Germany. He will come back tomorrow.

________ you ever _________ (do) a sponsored swim before? I want to do it this year so I'm asking for some advice at the moment.

My grandpa _____________ (not study) Latin when he was in school.

I ___________ (not organize) a jumble sale for two years. I don't know if I can do it again.

Dr. Dave already ___________ (set off) to Italy this morning.

Jenny _____________ (not be) to South Korea before. She wants to go there next summer.

My parents ______________ (never / be) to South Africa, but they'd love to.

Mr. John ___________ (write) five novels last year. He's such a hard-working writer.

Tanya ___________ (lose) her keys when she was in the US

Last year, Sarah ________ (sell) sweets to raise money.

______ you ______ (meet) a lot of people when you went to China?

I ________ (never / hear) this song. Who made it?

We ________ (have) three tests this week.

Gabriel __________ (be) my best friend ever. Then she went to France and we don't keep in touch anymore.