——________ did your uncle leave his home town?. ——Let me see. He _______ for nearly twenty years.
A:When; has left
B:When; has been away
C:How long; has left
D:How long; has been away
家鸽呼吸时,空气进入肺内的途径是( )
根据句意及首字母提示完成单词。
有一组对边平行的图形,一定是梯形.