Small edit of wording

Author: AbbyMSFT

articles/azure-monitor/alerts/alerts-create-new-alert-rule.md

@@ -90,7 +90,7 @@ And then defining these elements for the resulting alert actions using:
         |Threshold value|If you selected a **static** threshold, enter the threshold value for the condition logic. |
         |Unit|If the selected metric signal supports different units,such as bytes, KB, MB, and GB, and if you selected a **static** threshold, enter the unit for the condition logic.|
         |Threshold sensitivity| If you selected a **dynamic** threshold, enter the sensitivity level. The sensitivity level affects the amount of deviation from the metric series pattern is required to trigger an alert. |
-        |Aggregation granularity| Select the interval that is used to group the data points using the aggregation type function. Choose an **Aggregation granularity** (Period) that's greater than the **Frequency of evaluation** to reduce the likelihood of missing the first evaluation of added time series.|
+        |Aggregation granularity| Select the interval that is used to group the data points using the aggregation type function. Choose an **Aggregation granularity** (Period) that's greater than the **Frequency of evaluation** to reduce the likelihood of missing the first evaluation period of an added time series.|
         |Frequency of evaluation|Select how often the alert rule is be run. Select a frequency that is smaller than the aggregation granularity to generate a sliding window for the evaluation.|
 
     1. Select **Done**.