How do we know this strider is a friend of gandalf ?

我们怎么知道这个神行客是甘道夫的朋友？

Some doctors quit wearing ties , but not everyone was willing . So the committee bought a batch of antimicrobial ties from ms. strider .

一些医生不再打领带，但并不是每一个人都愿意，因此委员会从斯特赖德手里买来了一批抗菌领带。