Complex sentence: Parvati, when depicted alongside Shiva, generally appears with two arms, but when alone, she is depicted having four, eight or ten arms, and is astride on a tiger or lion.
Split into simpler sentences: Parvati, when depicted alongside Shiva, generally appears with two arms, but when alone, she may be depicted having four. In some manifestations, she has eight or ten arms, and is astride on a tiger or lion.