generate Corefile which uses your ISP's DNS servers to resolve domain names in China and uses OpenDNS/Cloudflare/Google DNS servers to resolve domain names outside China for CoreDNS. You should change 116.228.111.118 180.168.255.18 to your ISP's DNS server address or use public DNS server such as 114/DNSPod etc. directly.

gen_Corefile.sh

#!/bin/bash
echo ". {" > Corefile
echo "  forward . 208.67.222.222:443 208.67.222.222:5353 208.67.220.220:443 208.67.220.220:5353 tls://1.0.0.1 tls://8.8.8.8 tls://8.8.4.4  {" >> Corefile
china=`curl https://cdn.jsdelivr.net/gh/felixonmars/dnsmasq-china-list/accelerated-domains.china.conf -s | while read line; do awk -F '/' '{print $2}' | grep -v '#' ; done |  paste -sd " " -`
apple=`curl https://cdn.jsdelivr.net/gh/felixonmars/dnsmasq-china-list/apple.china.conf -s | while read line; do awk -F '/' '{print $2}' | grep -v '#' ; done |  paste -sd " " -`
google=`curl https://cdn.jsdelivr.net/gh/felixonmars/dnsmasq-china-list/google.china.conf -s | while read line; do awk -F '/' '{print $2}' | grep -v '#' ; done |  paste -sd " " -`
echo "  except $china $apple $google" >> Corefile
echo "  }" >> Corefile
echo "  proxy . 116.228.111.118 180.168.255.18" >> Corefile
echo "  log" >> Corefile
echo "  cache" >> Corefile
echo "  health" >> Corefile
echo "}" >> Corefile