✔ 最佳答案
i also agree they are almost equivalent (perhaps there's some slight difference that i dunno). one of the reasons i can imagine is the writer is trying to stress. by putting 2 adjectives in similar meanings together he adds more force to the meaning 'fear'. another famous example is the simultaneous use of SIMPLE and EASY:
e.g. It's simple and easy to bake a cake. Try it yourself!
in this occasion we both understand 'simple' and 'easy' are synonyms...do you think the writer can better express the meaning 'baking a cake is exceptionally easy' by using 'simple' or 'easy' alone?
this way of stress is better than repeating the same word, because it's more comfortable to read if they are different words but of similar senses.
i hope i can help a little bit.