Thanks hundres of thousands, Niall. I see.
How shoud I take the meaning that people is omitted instntly like you. Are there any clues? I wondered which was which.
For every person that achieves what he wants to achieve, there are hundreds of thousands of people that fail.
There are three clues that work together. The first clue is the word 'person'. The second is the structure of the sentence: 'for every ... there are ...'. The third is the plural verb 'are'. When you see 'for every x there is/are y' you can assume that if there's no subject of the second verb, you need to assume one. If the verb is 'are', assume a plural. You know that the subject is 'person', so make that a plural. (The plural of 'person' is usually 'people.)