Cách sử dụng
The expression "knock up" is commonly used in British English to mean "to wake someone up by knocking on their door or window early in the morning." However, in American English, this phrase has a different meaning which is "to cause a woman to become pregnant." Therefore, it's important for an English learner to understand the context and usage of the phrase before using it in a conversation. In most cases, it's best to avoid using this phrase altogether and opt for alternatives like "wake up" or "get someone up."