Idiom: to lend/give (someone) a hand; used as a verb.
Cristal: Hey Zac, I want to rearrange the furniture, but it's too heavy. Could you lend me a hand?
Zack: Of course. What do you want to move first?
Meaning: "to lend/give (someone) a hand" means to help someone; while not always, this idiom is often used when the help is physical in nature, such as Cristal asking Zack to help her move furniture. Usually, the request is made because an action is too difficult for one person alone, or because the action requires one additional hand, as in the example below.
James: My hands are full with groceries, and I can't open the door.
Molly: Here, let me give you a hand. Should I take some bags or get the keys out of your pocket?
Here, James only has two hands, which are filled with groceries, so he needs one more hand to get the keys out of his pocket and open the door. However, as in the first example, the idiom usually doesn't literally mean "I need your hand," and occasionally, the help isn't even physical, as in this example:
Al: My son Marty asked me about a Geometry problem, and I cannot figure it out. Henrietta, you're good at math. Could you give him a hand?
Henrietta: Sure, let me look. Hmm. Oh, I see the problem...
Meaning: In this case, Al's son Marty needs help with a math problem, which isn't physical. Notice that whether you use "lend" or "give" (either one is correct), the person being helped should be come between the verb and "a hand" (which is always singular).
This idiom is from LSI's book "Reading Horizons," which is used in the Level 6 Reading classes. For more information, please visit http://www.languagesystems.com/