When necessary, instinct is the most reliable resource you can fall back on.

必要时，本能是你可使用的最可靠的资源。

For the most reliable results, the system should be idle when you run this command.

为了获得最可靠的结果，在你运行这个命令时，系统应该是空闲的。

Even the most reliable waterpower varied with the seasons and disappeared in a drought.

即使是最可靠的水力也会随着季节变化，也会因干旱而消失。

For example, being the best hotel chain, or making the best, the most user friendly, or the most reliable products in a particular field.

例如，成为最好的连锁酒店，或者在某一特定领域里制造最好的、对用户最友好的、最可靠的产品。

Which have been the most reliable?

哪些又最可靠呢？