Unwanted echoes usually occur as distributed clutter, as surface clutter (such as land and sea echoes) or as volume clutter (such as rain, chaff).

The oleaginous salesman convinced me to buy a more expensive car.

The drive westward, regardless of towering mountain ranges, brought the opening late in 1940 of the 133-mile section of the Szechwan-Sikang highway from Yaan to Kangting (Tachienlu), which, together with the 93-mile stretch Chengtu-Yaan (completed by the Szechwan provincial authorities in 1934), established the first motor route from Szechwan to Sikang.

Memory barriers are necessary because most modern CPUs employ performance optimizations that can result in out-of-order execution.