好像出现在正确选项里的,都是help do,还没见过help to do的, 既然前者可以表达相同的意思, 那么加to就有不简洁之嫌了.不过个人觉得ets不太可能给两个一摸一样,就只有help do 和help to do有差别的选项, 大多数情况,一个句子有不止一处错误,可以结合多个语法点来选题

help to do 好像没错

help do 可能可以,至少在OG中是对的

help to do in OG-216

216. Many policy experts say that shifting a portion of health-benefit costs back to the workers helps to control the employer’s costs, but also helps to limit medical spending by making patients more careful consumers.

(A) helps to control the employer’s costs, but also helps

(B) helps the control of the employer’s costs, and also

(C) not only helps to control the employer’s costs, but also helps

(D) helps to control not only the employer’s costs, but（C）

(E) not only helps to control the employer’s costs, and also helps

看来help to do不能作为错误标志,要综合考虑选项.

Help DO:

236. The Coast Guard is conducting tests to see whether pigeons can be trained to help find survivors of wrecks at sea.

(A) to see whether pigeons can be trained to help find

(B) to see whether pigeons can be trained as help to find

(C) to see if pigeons can be trained for helping to find

(D) that see if pigeons are able to be trained in helping to find（A）

(E) that see whether pigeons are able to be trained for help in finding

Help to do

1.        Many policy experts say that shifting a portion of health-benefit costs back to the workers helps to control the employer’s costs, but also helps to limit medical spending by making patients more careful consumers.

(A) helps to control the employer’s costs, but also helps

(B) helps the control of the employer’s costs, and also

(C) not only helps to control the employer’s costs, but also helps

(D) helps to control not only the employer’s costs, but（C）

(E) not only helps to control the employer’s costs, and also helps

another Help DO:

        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（C）

(E) the maintenance of