Unfortunately the python plugin framework doesn't pretty-print, nor does lightning-cli, so best viewed with -H (sorry for all the slasshes in the output. nothing I can do about it at this point):

lightning-cli -H monitor

{
    \"num_connected\": 26,
    \"num_channels\": 37,
    \"states\": [
        \"CHANNELD_NORMAL: 37\"
    ],
    \"channels\": {
        \"CHANNELD_NORMAL\": [
            \"024a8228d764091fce2ed67e1a7404f83e38ea3c7cb42030a2789e73cf3b341365\	connected\	their fees\	xx.xx% owned by us\	537914x2372x0\",
            \"032e04b67641c00444af1d83145c0b63bac8316a6afb8fec0f87938295ed8bb129\	disconnected\	their fees\	xx.xx% owned by us\	539125x1288x0\",
            \"0279c22ed7a068d10dc1a38ae66d2d6461e269226c60258c021b1ddcdfe4b00bc4\	connected\	our fees\	xx.xx% owned by us\	539467x852x0\",
 	    ...
            \"0227d5b940cba21be92244953475ccdd3cefbed8f397be03e3155a5f41f304fc93\	connected\	their fees\	xx.xx% owned by us\	581418x2157x0\"
        ]
    }
}

As you can see you will see a list of channels to which you are connected or disconnected. How much percent of the funds is owned by you and who has to pay the fees in case of force channel closing.

Or if you just want to see the channels which are currently disconnected from peers

lightning-cli -H monitor | grep "disconnected"