diff --git a/src/replace-words.js b/src/replace-words.js
index 0266934..ddb8b10 100644
--- a/src/replace-words.js
+++ b/src/replace-words.js
@@ -234,7 +234,7 @@ function verbMethod(node, regexp, options) {
   let match = node.nodeValue.match(regexp);
   if (match == null) { return; }
   const verb = match[1];
-  const tense = match[2];
+  const tense = match[2].toUpperCase().replaceAll(" ", "_");
   const replace_value = verbsHelper.getConjugation(null, verb, tense, getPovIndex(options));
   node.nodeValue = node.nodeValue.replace(regexp, replace_value);
   verbMethod(node, regexp, options);
@@ -254,6 +254,7 @@ function pluralThirdVerbMethod(node, regexp, options) {
     verb = match[5];
     tense = match[6];
   }
+  tense = tense.toUpperCase().replaceAll(" ", "_");
   const replace_verb = verbsHelper.getConjugation(null, verb, tense, 2);
   let replace_value;
   if (wasBefore) {