My textbook says they are incorrect, but I fail to find their mistakes.
Many men still have difficulty accepting a woman to be a business partner.
At the daycare center, the teachers treated the children like their own children.
English Language Learners Stack Exchange is a question and answer site for speakers of other languages learning English. It only takes a minute to sign up.Sign up to join this community
The first sentence is grammatically correct, but does not sound natural. Probably the only usages of the wording accept someone to be are in religious writing, for example:
...we pray that you, a non-Christian yet, accept Him to be your personal Savior and Lord... - The favor of God our trinity
In this context, accept someone to be means starting something new- a transition- whereas in your sentence the intended meaning relates to something that will last for a while - a state. This can be better expressed using as or in the role of.
Many men still have difficulty accepting a woman as a business partner.
The second sentence is also grammatically correct, but ambiguous because the intended meaning has been subjected to some clumsy ellipsis. The intended meaning is:
At the daycare center, the teachers treated the children like they would treat their own children.
but it could be misinterpreted as
At the daycare center, the teachers treated the children as if they were their own children.
The difference is one of emphasis: the intended meaning relates to the way the teachers behave toward the children, but the unintended meaning relates more to possesion/parentage.
Taking the intended meaning and applying a more natural ellipsis, children should go first, and then treat next. We have to retain they would in order to avoid ambiguity:
At the daycare center, the teachers treated the children like they would treat their own.
At the daycare center, the teachers treated the children like they would their own.