Formal:
* 能帮忙 (néng bāngmáng): This is the most common and polite way to say "can help." It literally means "able to help."
* 可以帮忙 (kěyǐ bāngmáng): This is another formal way to say "can help." It literally means "can help."
* 请问您需要帮忙吗？ (qǐngwèn nín xūyào bāngmáng ma?): This is a very polite way to offer help, literally asking "Do you need help?"
Informal:
* 帮得上忙 (bāng de shàng máng): This means "able to help," and is more informal than "能帮忙."
* 可以 (kěyǐ): This is a very short and informal way to say "can," and can be used in the context of helping someone.
* 我帮你 (wǒ bāng nǐ): This means "I'll help you," and is a more direct way of offering help.
Examples:
* 能帮忙吗？(Néng bāngmáng ma?) (Can you help?)
* 请问您需要帮忙吗？ (Qǐngwèn nín xūyào bāngmáng ma?) (Do you need help?)
* 我帮您拿一下 (wǒ bāng nín ná yīxià) (I'll help you carry it)
* 您帮得上忙吗？ (Nín bāng de shàng máng ma?) (Are you able to help?)
The best way to say "can help" in Mandarin depends on the specific situation and your relationship with the person you are speaking to.