If there is a choir or solo singers their part is written near the bottom, above the strings. The bar lines will usually join up the staves of each family. This makes it easier to find the instruments than if they had been drawn all the way down the page. An experienced conductor knows score order well enough to examine a score and very quickly see which instrument plays a given part, even if the instrument names are not there. Below is an example of score order for a standard orchestral score as it would be listed alongside the staves.