23.Ideally, the professional career diplomat should help in the ongoing maintenance of an effective American foreign policy despite changes in administration. (A) in the ongoing maintenance of (B) in the maintaining of (C) maintain (D) to maintain and continue (E) the maintenance of
答案是C没问题,有谁能解释一下help do 和help to do的区别,如果有一个help to maitain 那该选哪一个啊? Thanks a lot