In the sentence 'They live in the country', the plural form of the verb 'live' is in agreement with the plural subject 'they'.

在They live in the country一句中，动词复数形式live与复数主语they一致。

《牛津词典》

If a child says to his mother, "I love you, Mommy", it's a very unusual parent who would say, "Oh, no. The verb agreement is mistaken."

如果孩子对他的妈妈说：“我爱你，妈妈”，很少有家长会说：“哦，不对。动词一致性错了。”

youdao

So for instance, if a child says to his mother, "I loves you, Mommy," it's a very unusual parent who would say, "Oh, no." The verb agreement is mistaken.

例如，如果孩子对妈妈说，“我爱你，妈妈”，很少有家长会说，“不对，动词一致性错了。”

youdao

"Everything from basic language skills of agreement of subject and verb, use of commas and other punctuation, complete and incomplete sentences, so that we can move from basic writing/language skills to the more sophisticated skills that graduate students, upper level undergraduates and people in the work world use."

VOA: special.2010.02.11

So for instance, if a child says to his mother, "I loves you, Mommy," it's a very unusual parent who would say, "Oh, no. The verb agreement is mistaken.

例如,如果孩子对妈妈说,"我爱你,妈妈",很少有家长会说,"不对,动词一致性错了

耶鲁公开课 - 心理学导论课程节选

For this reason, subject-verb agreement is of paramount importance.

BBC: WI v England - 1st ODI as it happened

Beware of common grammatical mistakes, like subject-verb agreement.

FORBES: Magazine Article