I believe that 1 and 2 are correct. After the verb "to help," you CAN use "to": a. He helped me to translate Mandarin. b. He helped me to translate Spanish. Since you are a learner, I respectfully suggest that you use the "to." It will help your listeners TO better understand what you are saying. As soon as your listener hears the "to," s/he may expect an infinitive. I believe that sentence 3 would be fine if you added a preposition: Can you help me IN improving my English? P.S. I think that many native speakers would use "could." It is considered more courteous. ***** Could you help me wash the dishes? Could you help me to wash the dishes? Could you help me in washing the dishes?

a) and b) are both fine, but a) is much more common. c) is wrong Can you help me cook dinner? Can you help me finish my homework?

a and b are both commonly used, but the answer here is a.