Complex sentence: The next day they encountered some opposition when the Yeomanry post on Hill 300, was threatened by 100 Ottoman cavalry, and one prisoner was captured, while one man was killed and another seriously wounded by shell fire.
Split into simpler sentences: The next day they encountered some opposition when the Yeomanry post on Hill 300 was threatened by 100 Ottoman cavalry. One man was taken prisoner, while one man was killed and another seriously wounded by shell fire.