changes from PR

Author: Sam Kleinman

source/tutorial/backup-sharded-cluster-with-filesystem-snapshots.txt

@@ -29,7 +29,7 @@ up of the :term:`config database`, and then take backups of each
 shard in the cluster using a file-system snapshot tool. If you need an
 exact moment-in-time snapshot of the system, you will need to stop all
 application writes before taking the filesystem snapshots; otherwise
-the snapshot will only approximate a moment of in time.
+the snapshot will only approximate a moment in time.
 
 For approximate point-in-time snapshots, you can improve the quality
 of the backup while minimizing impact on the cluster by taking the
@@ -47,7 +47,7 @@ shard.
       It is essential that you stop the balancer before creating
       backups. If the balancer remains active, your resulting backups
       could have duplicate data or miss some data, as :term:`chunks
-      <chunk>` migrate while recording backups.
+      <chunk>` may migrate while recording backups.
 
 #. Lock one member of each replica set in each shard so that your
    backups reflect the state of your database at the nearest possible