下列词语中画线字的注音，正确的一项是（ ）

eory wasn’t accepted by many peoplewhen it was first ____, but it proved to be true as time went by.

Have you ever _____ Mudanjiang to see the Jingbo Lake—Yes, I have.

mes to get out of difficulty, one must change his way of thinking, or simply change his ___________ towards a problem.

There ‘s some difficulty in _____ such little children. [ ]