首先它说了3.Tom needs a gym instructor like James. 这个句子是有问题的，这个我能理解。比较对象会出现ambiguity。
然后又举了个
In the above sentence, the comparison is between ‘I’ and ‘my brother’. My brother wants to be an investment banker, and so do I. This same meaning can be conveyed if we say:
I want to be an investment banker, like my brother. (‘I’ compared with ‘investment banker’)
为毛这句话不会产生ambiguity？可以是I & my brother或者 Inverstment Banker & my brother的对比啊。。
1. When ‘like + noun’ is separated from the sentence by a comma, the comparison is between the subject of the sentence and the noun following ‘like’.
2. When ‘like + noun’ is not separated from the sentence by a comma, the comparison is between the object of the sentence and the noun that follows ‘like’. Note that this usage is correct only when there is no ambiguity about which two nouns are being compared.