Sign in
|
English
|
Terms of Use
Dictionary
Forum
Contacts
Chinese
⇄
Afrikaans
Arabic
Catalan
Danish
Dutch
English
Estonian
Finnish
French
German
Greek
Hungarian
Icelandic
Italian
Korean
Lithuanian
Norwegian Bokmål
Polish
Portuguese
Romanian
Russian
Slovene
Spanish
Swedish
Turkish
Ukrainian
G
o
o
g
l
e
|
Forvo
|
+
两极抽样，两阶段抽样
math.
two-stage sample
Add
|
Report an error
|
Get short URL
|
Language Selection Tips
