The word(s) "understand" appears 127 time(s) in 127 verse(s) in Quran in Abdullah Yusuf Ali translation.

(31) But (even so), if they repent, establish regular prayers, and practise regular charity,- they are your brethren in Faith: (thus) do We explain the Signs in detail, for those who understand.

(32) The Hypocrites, men and women, (have an understanding) with each other: They enjoin evil, and forbid what is just, and are close with their hands. They have forgotten Allah; so He hath forgotten them. Verily the Hypocrites are rebellious and perverse.

(33) Those who were left behind (in the Tabuk expedition) rejoiced in their inaction behind the back of the Messenger of Allah: they hated to strive and fight, with their goods and their persons, in the cause of Allah: they said, "Go not forth in the heat." Say, "The fire of Hell is fiercer in heat." If only they could understand!

(34) They prefer to be with (the women), who remain behind (at home): their hearts are sealed and so they understand not.

(35) Whenever there cometh down a Sura, they look at each other, (saying), "Doth anyone see you?" Then they turn aside: Allah hath turned their hearts (from the light); for they are a people that understand not.

(36) It is He Who made the sun to be a shining glory and the moon to be a light (of beauty), and measured out stages for her; that ye might know the number of years and the count (of time). Nowise did Allah create this but in truth and righteousness. (Thus) doth He explain His Signs in detail, for those who understand.

(37) Say: "If Allah had so willed, I should not have rehearsed it to you, nor would He have made it known to you. A whole life-time before this have I tarried amongst you: will ye not then understand?"

(38) Among them are some who (pretend to) listen to thee: But canst thou make the deaf to hear,- even though they are without understanding?

(39) Is it not (the case) that to Allah belongeth whatever is in the heavens and on earth? Is it not (the case) that Allah's promise is assuredly true? Yet most of them understand not.

(40) No soul can believe, except by the will of Allah, and He will place doubt (or obscurity) on those who will not understand.