man crond shows the following (my comment are with ***):

CRON(8)                                                                CRON(8)

NAME
       cron - daemon to execute scheduled commands (cronie V1.2)

SYNOPSIS
       cron [-n | -p | -m<mailcommand>]
       cron -x [ext,sch,proc,pars,load,misc,test,bit]

*** cron? there is no "cron" command, it's *crond*. (Thre is even "man cron" manpage alias, but there is no actual "cron" *command*).

...
       There are two ways, how the changes  are  checked  in  crontables.

*** The comma is perhaps not needed. I'd also replace "crontables" with "crontabs".

       The
       first  is  checking  the modtime of file and the other is using inotify
       support.

*** I am no expert, but it looks like slightly broken English, should be "The first METHOD is ... and the other ONE is ..."

       You can find out which of them are you using,  if  you  check
       /var/log/cron where is (or isn’t) inotify mentioned after start of dae-
       mon.

*** More English breakage. I propose "You can find out which of them are in use by checking crond log (see whether it mentions inotify or not)"

       The inotify support is watching for changes in all crontables  and
       touch the disk only in case that something was changed.

       In  other case cron checks each minute to see if its crontables modtime
       have changes and reload those which have changes.

*** More. crontables -> crontabs' , reload -> reloads

       There is no  need  to
       restart  cron  after  some of the crontable is modified.

*** crontable -> crontabs

       This option is
       used also when inotify couldn’t be initialized.

       Cron is  checking  those  files  or  directories:

*** Cron is  checking -> Crond checks

       /etc/crontab  system
       crontab   is  usually  for  running  daily,  weekly,  monthly  jobs.
       /etc/cron.d/ where are system cronjobs stored for  different  users.

*** Badly phrased.

       /var/spool/cron that’s mean spool directory for user crontables.

*** "mean spool directory"? It's basically means "bad spool directory" :D

       Note  that  the  crontab(1)  command  updates  the modtime of the spool
       directory whenever it changes a crontab.

...


       -n     This  option changes default behavior causing it to run crond in
              the foreground.  This can be useful  when  starting  it  out  of
              init.

*** What first word "it" refers to in the text above? I'd replace the whole first sentence with: "Run in foreground."

       -p     Cron permit any crontab, which user set.

*** I don't understand what manpage is trying to say here.

       -x     With this option is possible to set debug flags.

*** How about just: " -x FLAG    Set debug flag". Can I specify more than one flag?