fix: wording

website/advanced/core-concepts.md

@@ -107,7 +107,7 @@ We can use double dollar `$$VAR` to _include unnamed nodes_ in the pattern resul
 
 Sometimes, using kind alone is not enough to find the nodes we want. A node may have several children with the same kind, but different roles in the code. For [example](https://ast-grep.github.io/playground.html#eyJtb2RlIjoiQ29uZmlnIiwibGFuZyI6ImphdmFzY3JpcHQiLCJxdWVyeSI6ImNvbnNvbGUubG9nKCRNQVRDSCkiLCJjb25maWciOiJydWxlOlxuICBraW5kOiBzdHJpbmciLCJzb3VyY2UiOiJ2YXIgYSA9IHtcbiAgJ2tleSc6ICd2YWx1ZSdcbn0ifQ==), in JavaScript, an object may have multiple keys and values, all with the string kind.
 
-To distinguish them, we can use `field` to specify the relation between a node and its parent. In ast-grep, `field` is specified in two [relational rules](/guide/rule-config/relational-rule.html#relational-rule-mnemonics): `has` and `inside`.
+To distinguish them, we can use `field` to specify the relation between a node and its parent. In ast-grep, `field` can be specified in two [relational rules](/guide/rule-config/relational-rule.html#relational-rule-mnemonics): `has` and `inside`.
 
 `has` and `inside` accept a special configuration item called `field`. The value of `field` is the _field name_ of the parent-child relation. For example, the key-value `pair` in JavaScript object has two children: one with field `key` and the other with field `value`. We can use [this rule](https://ast-grep.github.io/playground.html#eyJtb2RlIjoiQ29uZmlnIiwibGFuZyI6ImphdmFzY3JpcHQiLCJxdWVyeSI6ImNvbnNvbGUubG9nKCRNQVRDSCkiLCJjb25maWciOiJydWxlOlxuICBraW5kOiBzdHJpbmdcbiAgaW5zaWRlOlxuICAgIGZpZWxkOiBrZXlcbiAgICBraW5kOiBwYWlyIiwic291cmNlIjoidmFyIGEgPSB7XG4gICdrZXknOiAndmFsdWUnXG59In0=) to match the `key` node of kind `string`.