The answer is b: to travel along a usual route.

答案是 b：沿着通常的路线行驶。

The usual routes the aid agencies use from Turkey south into Syria are now blocked.

从土耳其南部到叙利亚之间被援助机构用来运输的线路已被封锁。

The next day, he set off on his usual route.

第二天，他就按照往常的路线出发了。

If the usual route is blocked by an accident, he goes by some other route.

如果通常的路线因事故而受阻， 他就会走另一条路线。

Well, I figured it was time to get back to work, so I put together a speaking tour—Seattle, Portland, my usual route.

我觉得是时候回去工作了，所以定了个演讲行程，我的惯驶航线是西雅图到波特兰。

When it comes to defence tech, the usual route of an initial public offering does not look promising.

在国防科技领域，传统的首次公开募股（IPO）路径似乎前景黯淡。

" TH. GENOIS, Recorder." On the 8th we came to Lake Pontchartrain, by railroad, and, in due time, following the usual route, reached Charleston.

GENOIS， 记录员。 ” 8 日，我们乘铁路来到庞恰特雷恩湖， “TH.并在适当的时候， 沿着通常的路线到达查尔斯顿。

Every afternoon before I leave work, I listen to the traffic report to see if I should take my usual route home or make a detour.

每天下午下班前，我都会听听路况报告， 看看是应该走平时的路线回家， 还是绕道而行。

While some of the already oxygenated blood leaks back to the lungs, most of it goes the usual route to the aorta and the baby appears pink as normal.

一些已经氧化的血液流回道双肺，同时大部分血液按正常途径进入主动脉，婴儿像正常时一样呈现粉红色。