(1) Half an hour went by, but the last bus hasn't come. We had to walk home.

由“過去了”知句子時態(tài):一般過去時；這兩個句子為并列句。

(2) Mary seems to be worried about the Chinese exam because she hasn't learnt the text by heart.

時態(tài):現(xiàn)在完成時；主干:瑪麗對考試擔(dān)心；句間關(guān)系為因果關(guān)系。

(3) Since the basketball match has been postponed, we may as well visit the museum.

由“已被推遲”知句子時態(tài):現(xiàn)在完成時的被動語態(tài)。

(4) During the World War ll, he lived in Australia with his parents all the way.

由“二次世界大戰(zhàn)”知句子時態(tài):一般過去時；主干:他和父母住在澳大利亞。

(5) Since I graduated from Nanjing University in1985, I have kind of lost touch with my college classmates.

由“自1985年……至今”知句子時態(tài):現(xiàn)在完成時；主干:我與大學(xué)同學(xué)失去了聯(lián)系。