 Complete the following phrase:  In July 1917, the Russo-Romanian forces commanded by General Alexandru Averescu defeated the Austro-German forces at Mărăști, but they failed to develop further success due to the telegram from the minister-chairman of the Provisional Government, Alexander Kerensky, who ordered the stop of the offensive in connection with the German breakthrough at Tarnopol. In late July to August 1917, the Russo-Romanian forces successfully repelled the Austro-German forces led by German Generalfeldmarschall August von Mackensen at 