diff --git a/core/lib/Drupal/Core/Extension/ModuleInstaller.php b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
index dba7a94..ec0bcb4 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
@@ -345,7 +345,7 @@ public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
       foreach ($reasons as $reason) {
         $reason_message[] = implode(', ', $reason);
       }
-      throw new ModuleUninstallValidatorException(format_string('The following reasons prevents the modules from being uninstalled: @reasons', array(
+      throw new ModuleUninstallValidatorException(format_string('The following reasons prevent the modules from being uninstalled: @reasons', array(
         '@reasons' => implode(', ', $reason_message),
       )));
     }
diff --git a/core/modules/system/css/system.admin.css b/core/modules/system/css/system.admin.css
index 7f23aab..959a908 100644
--- a/core/modules/system/css/system.admin.css
+++ b/core/modules/system/css/system.admin.css
@@ -157,7 +157,8 @@ small .admin-link:after {
   margin-bottom: 0;
 }
 .admin-requirements,
-.admin-required {
+.admin-required,
+.validation-reasons {
   font-size: 0.9em;
   color: #666;
 }
diff --git a/core/modules/system/src/Form/ModulesUninstallForm.php b/core/modules/system/src/Form/ModulesUninstallForm.php
index ec1a0ea..e8fb208 100644
--- a/core/modules/system/src/Form/ModulesUninstallForm.php
+++ b/core/modules/system/src/Form/ModulesUninstallForm.php
@@ -175,9 +175,9 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       if (isset($validation_reasons[$module_key])) {
         $disabled_message = \Drupal::translation()->formatPlural(count($validation_reasons[$module_key]),
           'The following reason prevents @module from being uninstalled: @reasons',
-          'The following reasons prevents @module from being uninstalled: @reasons',
+          'The following reasons prevent @module from being uninstalled: @reasons',
           array('@module' => $module->getName(), '@reasons' => implode('; ', $validation_reasons[$module_key])));
-        $disabled_message .= '<div class="validation_reasons">' . $disabled_message . '</div>';
+        $disabled_message = '<div class="validation-reasons">' . $disabled_message . '</div>';
       }
 
       $form['uninstall'][$module->getName()]['description']['uninstall']['#markup'] = $this->t($disabled_message);
diff --git a/core/modules/system/src/Tests/Field/FieldModuleUninstallValidatorTest.php b/core/modules/system/src/Tests/Field/FieldModuleUninstallValidatorTest.php
index f427ade..d571e4b 100644
--- a/core/modules/system/src/Tests/Field/FieldModuleUninstallValidatorTest.php
+++ b/core/modules/system/src/Tests/Field/FieldModuleUninstallValidatorTest.php
@@ -83,7 +83,7 @@ public function testUninstallingModule() {
     }
     catch (ModuleUninstallValidatorException $e) {
       $this->pass($message);
-      $this->assertEqual($e->getMessage(), 'The following reasons prevents the modules from being uninstalled: There is data for the field extra_base_field on entity type Test entity.');
+      $this->assertEqual($e->getMessage(), 'The following reasons prevent the modules from being uninstalled: There is data for the field extra_base_field on entity type Test entity.');
     }
 
     // Verify uninstalling entity_test is not possible when there is content for