Use Present Perfect or Present Perfect Progressive:

1) The girls (dance) since 3 p.m.

2) They (travel) for a month already.

3) Sue (know) Sally all her life.

4) Alice always (want) to visit Finland.

5) I (read) this book for two hours already.

The girls have been dancing since 3 p.m.They have been travelling for a month already. Sue has known Sally all her life. Alice has always wanted to visit Finland I have been reading this book for two hours already.