diff --git a/framework/helpers/BaseHtml.php b/framework/helpers/BaseHtml.php
index 735950a..10dca74 100644
--- a/framework/helpers/BaseHtml.php
+++ b/framework/helpers/BaseHtml.php
@@ -743,7 +743,7 @@ class BaseHtml
     /**
      * Generates a drop-down list.
      * @param string $name the input name
-     * @param string $selection the selected value
+     * @param string|array $selection the selected value(s). String for single or array for multiple selection(s).
      * @param array $items the option data items. The array keys are option values, and the array values
      * are the corresponding option labels. The array can also be nested (i.e. some array values are arrays too).
      * For each sub-array, an option group will be generated whose label is the key associated with the sub-array.
@@ -792,7 +792,7 @@ class BaseHtml
     /**
      * Generates a list box.
      * @param string $name the input name
-     * @param string|array $selection the selected value(s)
+     * @param string|array $selection the selected value(s). String for single or array for multiple selection(s).
      * @param array $items the option data items. The array keys are option values, and the array values
      * are the corresponding option labels. The array can also be nested (i.e. some array values are arrays too).
      * For each sub-array, an option group will be generated whose label is the key associated with the sub-array.
@@ -858,7 +858,7 @@ class BaseHtml
      * A checkbox list allows multiple selection, like [[listBox()]].
      * As a result, the corresponding submitted value is an array.
      * @param string $name the name attribute of each checkbox.
-     * @param string|array $selection the selected value(s).
+     * @param string|array $selection the selected value(s). String for single or array for multiple selection(s).
      * @param array $items the data item used to generate the checkboxes.
      * The array keys are the checkbox values, while the array values are the corresponding labels.
      * @param array $options options (name => config) for the checkbox list container tag.
@@ -938,7 +938,7 @@ class BaseHtml
      * Generates a list of radio buttons.
      * A radio button list is like a checkbox list, except that it only allows single selection.
      * @param string $name the name attribute of each radio button.
-     * @param string|array $selection the selected value(s).
+     * @param string|array $selection the selected value(s). String for single or array for multiple selection(s).
      * @param array $items the data item used to generate the radio buttons.
      * The array keys are the radio button values, while the array values are the corresponding labels.
      * @param array $options options (name => config) for the radio button list container tag.
@@ -1672,8 +1672,7 @@ class BaseHtml
 
     /**
      * Renders the option tags that can be used by [[dropDownList()]] and [[listBox()]].
-     * @param string|array $selection the selected value(s). This can be either a string for single selection
-     * or an array for multiple selections.
+     * @param string|array $selection the selected value(s). String for single or array for multiple selection(s).
      * @param array $items the option data items. The array keys are option values, and the array values
      * are the corresponding option labels. The array can also be nested (i.e. some array values are arrays too).
      * For each sub-array, an option group will be generated whose label is the key associated with the sub-array.