一向 / 时刻 / 仍旧 / 依旧: all along, constantly, still
【五05】时间副词 / adverbs
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
Four adverbs of continuity, placed before the verb or adjective: 一向 ("all along, always up to now": a long-standing trait or habit), 时刻 ("at every moment, constantly"), 仍旧 and 依旧 ("still, as before", when you might have expected a change).
一向 is not 一直: 一直 covers a specific uninterrupted stretch (我昨天一直在家), whereas 一向 describes a character or habit (他一向不爱说话) and takes no 了. 时刻 is not 随时: 时刻 means "at every moment, without a break" (时刻注意安全), 随时 "at any moment you like" (你随时可以来). Note that 时刻 is also a noun (关键时刻, "a crucial moment").
仍旧 and 依旧 are close to 仍然 (level 4) and to 还. They often follow a clause that mentions time passing or a change (十年过去了，他依旧住在那里). 依旧 is a little more literary and can even end the sentence (风景依旧, "the scenery is as it always was").
Examples
他一向不爱说话。
Tā yíxiàng bú ài shuōhuà.He has never been much of a talker.
我们家一向早睡早起。
Wǒmen jiā yíxiàng zǎo shuì zǎo qǐ.Our family has always gone to bed early and got up early.
开车的时候，要时刻注意安全。
Kāi chē de shíhou, yào shíkè zhùyì ānquán.When you drive, you must keep safety in mind at every moment.
她在国外工作，却时刻想念着家人。
Tā zài guówài gōngzuò, què shíkè xiǎngniàn zhe jiārén.She works abroad, yet she misses her family all the time.
十年过去了，他依旧住在那个小村子里。
Shí nián guòqù le, tā yījiù zhù zài nàge xiǎo cūnzi li.Ten years have gone by, and he still lives in that little village.
虽然下着大雨，比赛仍旧按时开始了。
Suīrán xià zhe dàyǔ, bǐsài réngjiù ànshí kāishǐ le.Although it was pouring, the match started on time all the same.
Common mistakes
✗ 我昨天一向在家 → ✓ 我昨天一直在家 (一向 describes a habit up to now, not a single day).
✗ 你时刻可以给我打电话 → ✓ 你随时可以给我打电话 (时刻 = "constantly", 随时 = "at any moment").
✗ 他一向喜欢咖啡了 → ✓ 他一向喜欢咖啡 (一向 describes a lasting state: no 了).