Collins Chinese Dictionary Plus (3rd edition), 2011:
一直 yīzhí 副
1
(=不变向) straight
- 一直走到十字路口,再向右拐(枴)。 Yīzhí zǒu dào shízì lùkǒu,zài xiàng yòu guǎi. Go straight ahead to the crossroads, then turn right.
- 顺(順)着(著)这(這)条(條)大街一直走500米就到了。 Shùnzhe zhè tiáo dàjiē yīzhí zǒu wǔbǎi mǐ jiù dào le. Follow this avenue for five hundred metres and you'll be there.
2 (=不间断) always
- 这(這)个(個)牌子的电(電)视(視)一直很受欢(歡)迎。 Zhège páizi de diànshì yīzhí hěn shòu huānyíng. This brand of TV has always been very popular.
- 大风(風)一直刮(颳)了两(兩)天两(兩)夜。 Dàfēng yīzhí guāle liǎng tiān liǎng yè. The gale blew for two days and two nights.
3 (指一定范围) all the way
- 从(從)南一直到北 cóng nán yīzhí dào běi from the north all way to the south
- 从(從)最北一直到最南,这(這)股寒流袭(襲)击(擊)了整个(個)国(國)家。 Cóng zuì běi yīzhí dào zuì nán,zhè gǔ hánliú xíjīle zhěnggè guójiā.
The cold current hit the country from the north all the way to the south.
- 他被雨淋得从(從)头(頭)顶(頂)一直湿(濕)到脚(腳)底。 Tā bèi yǔ lín de cóng tóudǐng yīzhí shī dào jiǎodǐ.
The rain soaked him from head to foot.