You use approximately before a number, time, or position to say that it is close to the correct one but is not exact.
近义词
roughly , about , around
双语例句
例： Approximately $150 million is to be spent on improvements.
大概会花费1.5亿美元用于改进。
例： Each session lasted approximately 30 to 40 minutes.
每一部分大概持续了30到40分钟。