真核生物成熟mRNA的两端均带有游离的3'-OH。( )

单项选择题听力原文：What is the woman's job?(15)A.A saleswoman.B.A clerk at the information desk.C.A clerk at the booking officE.D.An air-hostess.

单项选择题在一定工作领域内运用技术、工具、方法等的能力称为()