【判断题】[+sonorant] is only shared by all the vowels.()
【单选题】在藻类生活史中,核相交替与世代交替关系不正确的是
【多选题】在藻类植物生活史中,核相交替与世代交替的关系正确的是( )。
【单选题】在藻类植物的生活史中,核相交替与世代交替的关系不正确的是( )。
【多选题】Which of the following statements is/are correct about vowels?
A.
Vowels are produced without significant constriction of the air flowing through the mouth.
B.
There are 28 vowel sounds in English.
C.
Vowels refer to the sounds in spoken language that are made with no obstruction of air flow in the mouth.
D.
All vowels are voiced.
【简答题】小样本情况下,总体服从正态分布,总体方差已知,总体均值在置信水平(1-α)下的置信区间为( )
【简答题】大样本情况下,总体服从正态分布,总体方差已知,总体均值在置信水平(1-α)下的置信区间为( )
【判断题】The long vowels are all tense vowels and the short vowels are lax vowels.
【单选题】在参数估计中利用t分布构造总体均值置信区间的条件是( )。
【简答题】The long vowels are all tense vowels and the short vowels are l______ vowels.