Yes, type "U" refers to Unknown for the Nominal Annual Rate.

是的，“U”型指的是未知的名义增长率。

youdao

U - number of unknown answers in the first pass of the repetition, i.e. the number of questions that have one or more dots in their first column of the repetition scores field.

U -没答对问题的个数，也就是在重复学习评分栏里有一个或多个点的问题个数。

youdao

Many drugs obtained from foreign sources that claim or appear to be the same as U. S. -approved drugs are, in fact, of unknown quality and may even be counterfeit.

许多来自国外药品看似与美国批准的药品一模一样，事实上，质量未知，甚至可能是假冒的。

youdao

First of all, that bearded man who hosts the spots to his French soccer legend, Eric Cantona, who is totally unknown to U.S. viewers.

NPR: Slate's Ad Report Card: Soccer Stars in the Spotlight

The concept of the Protector was largely unknown in the U.S. and nearly always confined to offshore trusts thought the 1990s.

FORBES: Trust Protectors -- What They Are And Why Probably Every Trust Should Have One

At the time, Asus was a relative unknown in the U.S. cellphone market though its PCs, particularly its Eee PC netbooks, were popular among Americans, explains Lin.

FORBES: Asus Tried Windows Phone 7 Two Years Ago, Assessing Whether To Try Again