[DiogenesKynikos]

Recognizing and writing characters are different skills. Chinese people typically recognize far more characters than they can write (this has become much more severe in the electronics age, because most people input text using the pinyin Romanization, so they don't write by hand any more).

In addition, if you're reading a text and you come across an uncommon character, you can often figure it out, both from context and by recognizing elements in the character (which give hints about the pronunciation and meaning).

[EdwardDiego]

True, and the context of "use them" was indeed writing them.