The charity received an anonymous letter enclosing a large donation.慈善机构收到了一封附有一大笔捐赠的匿名信。We received an anonymous letter.我们收到一封匿名信。I enclose a Xerox of the anonymous letter.兹附上匿名信的复印件一份。He sent the anonymous letter to me as a jog toward the planned frame-up.他把匿名信寄给我，暗示我该开始进行计划好的诬陷活动了。