The two teachers were standing to one side, watching their students and talking in low tones.
The two stood talking in low tones for several minutes.
For a few minutes we stood thus talking in low tones.
She was talking in low tones with the three other men.
The four of them put their heads together, talking in low tones.
Nobody was left but a couple of the staff, talking together in low tones.
Then they, too, set off, talking in low tones to each other.
The two men across the way did not say anything at first, and then began talking in low tones.
The two of them walked away talking in low tones.
A woman and two men sat there, talking in low tones.