Present Perfect vs. Present Perfect Continuous

Jane (eat) the same kind of frozen meal five times this week.

Ann (know) Natalia for about three years now.

Amanda (worry) about her hair contantly since we arrived at the party.

Actuually, I can speak German, so I (understand) everything you said about me.

Jake (sing) the same song all morning. It's driving me crazy.

Tom and Beth (meet) in secret since their parents told them to stop seeing each other.

I (see) most of his paintings. They are all amazing!

How long you (have) this painting by Picasso?

I (have) a cold for two days.

They (learn) English for three years.