A microscope is a scientific instrument which makes very small objects look bigger so that more detail can be seen.
PHRASE
（通常由于被認為存在問題)被仔細研究
If you say that something is under the microscope, you mean that it is being studied very closely, usually because it is believed that something is wrong with it.
例句
The media put their every decision under the microscope.媒體仔細研究了他們的每一個決定。