Mr Baker ...... (know) his best friend for over twenty years.

Most of the students ...... (not / understand) the use of the Present Perfect the first time the teacher explained it.

Some of my friends ...... (go) to Switzerland on holiday this year. I hope they bring me back some lovely presents.

Mr and Mrs Johanson ...... (be) in Sudan three times this year.

The receptionist ...... (drop) the pen once again.

The spokesperson ...... (not / reveal) any secret information to the press.

The pupils ...... (wait) for their teacher for over an hour now.

Those secret agents ...... (search) the premises of the abandoned factory for two or three hours now. Look! You can still see their cars in front of the building.

The anchor ...... (just / comment) on the latest headlines.

The couple ...... (take) a lot of long strolls in the woods recently.

The children ...... (fly) kites the whole weekend.

The dry cleaner ...... (work) day and night to earn some extra money.