至 + Time + 为 + 止
The character 止 (zhǐ) means "to stop" or "up to" and frequently appears in set phrases to mark a boundary or endpoint. It is commonly found in the expression 为止 (wéizhǐ), meaning "up to" or "until," as in 至今为止 (up to now).
报名截止到本月底为止。
Bàomíng jiézhǐ dào běn yuè dǐ wéizhǐ.
Registration closes at the end of this month.
到目前为止,一切都很顺利。
Dào mùqián wéizhǐ, yīqiè dōu hěn shùnlì.
So far, everything has been going smoothly.
这个优惠活动到下周五为止。
Zhège yōuhuì huódòng dào xià zhōuwǔ wéizhǐ.
This promotional event lasts until next Friday.