大便隐血试验呈持续阳性常提示（）

A.急性胃黏膜病变

B.胃溃疡

C.十二指肠壶腹部溃疡

D.慢性萎缩性胃炎

E.胃癌

Which one of the following statements about the t - distribution is TRUE（）

A. The t- distribution is the appropriate distribution to use when constructing confidence intervals based on large samples.

B. Compared to the normal distribution, the t -distribution is more peaked with more area under the tails.

C. The t - distribution approaches the standard normal distribution as the number of degrees of freedom becomes large.