发音：[ˌæsərˈteɪn]
例句：
- The verb ascertain means to find out and determine something; More importantly, it is a formal word, which is usually used to express the meaning of discovering the facts or truth through examination or experimentation.
- Nowadays, although there tons of information on the internet, the truly valuable ones are increasingly hard to be ascertained.
- Russia has lost more than 15,000 troops, according to comments in late July by the head of the CIA, who said it was difficult to ascertain an exact number.
- The professor’s study surveyed 561 people to ascertain whether couples who used those strategies were getting on with their partners better during the pandemic, and found that they did.
- We use mathematical and computational techniques to ascertain whether or not the digital media—images, audio, and video—has been manipulated by some wrongdoers.
解释：
- Ascertain这个单词为动词，表示“discover the facts or truth by experimenting or examining”这一含义，即“查明/弄清/确认/确定”，与discover/confirm/verify/double-check这些单词构成近义词。另外，该单词通常用于书面正式场合。
- 具体使用场景如下：
- About 80 homes have been evacuated and road closures will remain in place until engineers ascertain the area is safe.（大约80所房屋已被疏散，道路封闭将继续存在，直到工程师确定该地区是安全的。）
—News - Authorities are still trying to ascertain the number of displaced households and the full extent of damages caused by the disasters.（当局仍在努力确定流离失所家庭的数量以及灾害造成的全部损失。）
—News - Nielsen Media Research, the television-ratings company, will be partnering with Facebook to ascertain what television viewers are watching on their tablets and other mobile devices.（电视评级公司尼尔森媒体研究公司将与Facebook合作，以确定电视观众在平板电脑和其他移动设备上观看的内容。）
—Business
