unhappy,when,a long time,areleft,some,are,they,dogs,for,alone,very.连词成句
问题描述：
unhappy,when,a long time,areleft,some,are,they,dogs,for,alone,very.连词成句
答
Some dogs are very unhappy when they are left alone for a long time.
有些狗独自呆着太久了就会非常不开心.
they是指代“some dogs”,所以不能放在句首而应当在some dogs 之后出现.