Sirius and Remus can come and go, but Tonks is stuck because she can't Apparate and no one can risk using the Floo anymore. And Sirius tries not to go unless he has to do, since you know he gets sick when he Apparates.

And then a few days ago Mr Snape invited Professor Sinistra to the potions lab. I've absolutely no idea why. She's no skill at Potions and--well, it was just ever so irritating. We don't need her help.

(I'm not even sure what she's meant to do in the Order, now she's not teaching anymore. Or, well, I suppose she's going to teach at Moddey a little. But I hope she doesn't keep coming to watch us brewing or talk with us while we're brewing or whatever it was he wanted her to do. If she comes again, I'm going to Sherwood, even though Tim says it's getting more and more dangerous.)