Examples

不着边际的长篇大论

a long rambling talk → 不着边际

他越讲越不着边际。

The more he talked, the further he strayed from the point. → 不着边际

他做起报告来，东拉西扯不着边际。

When he lectures he often strays from the subject. → 东拉西扯

他说话总是不着边际。

When he's talking he never sticks to the point. → 着

不着边际。 → 着

他讲话常常不着边际。 → 边际

a desultory conversation

不连贯的交谈，不着边际的闲扯 → desultory

They talk round the problem all evening.

整个晚上他们都在不着边际地谈这个问题。