1.   She was on the verge of ignoring the summons, on the reasonable assumption that the visitor had pressed the wrong buzzer, when it sounded several more times.

2.   Heavy explosions sounded several times a minute as Russian forces softened up rebel positions by lobbing round after round into the village.

3.   Heavy explosions sounded several times a minute.

4.   In Samashky, heavy explosions sounded several times a minute as Russian forces softened up rebel positions by lobbing round after round into the village.

5.   On Sunday, heavy explosions sounded several times a minute as Russian forces softened up rebel positions by lobbing round after round into Samashky.

6.   On Sunday, explosions sounded several times a minute as Russian forces softened up rebel positions by lobbing round after round into Samashky.