妙辨异同一步prepare (for),be ready/happen,take place

(a) They are preparing to do it. (正在准备)

(b) They are ready to do it. (准备好或愿意)

〔注〕 prepare意为“准备”,be ready意为“准备好”。 prepare(准备)不一定be ready(准备好)，但be prepared=be ready，后接不定式，是“愿意(而且能够)”的意思。