>>165
どうしてプロなのに答えられないんだい？
自分の誤訳に気づかないか？

The custom of conductors only beating time, rather than playing as well,
emerged only after 1820, particularly for complicated works such as operas.
Until late in the nineteenth century, solo concertos for piano were led by
the soloist, who supplied rhythmical support to the tutti passages in the
form of a basso continuo realisation. The concertmaster, on a higher chair,
led orchestra with his bow at difficult entries. In both the manuscript and
the early editions of both piano concertos, a basso continuo is figured or
written out, also providing additional evidence that these works were
performed by small ensembles.

ほら、これが原文だよ。