Apex domains cannot have CNAME records.
Question and response
Question
dig qq.com. NS
Answer
qq.com. 5 NS ns3.qq.com.
qq.com. 5 NS ns1.qq.com.
qq.com. 5 NS ns2.qq.com.
qq.com. 5 NS ns4.qq.com.
Authority
The response has no authority records.
Additional
ns1.qq.com. 5 A 43.166.55.2
ns1.qq.com. 5 A 112.90.13.140
ns1.qq.com. 5 A 180.153.217.98
ns1.qq.com. 5 A 183.60.116.2
ns1.qq.com. 5 A 203.205.220.251
ns2.qq.com. 5 A 1.12.96.10
ns2.qq.com. 5 A 43.129.131.210
ns2.qq.com. 5 A 43.159.167.132
ns2.qq.com. 5 A 49.7.250.140
ns3.qq.com. 5 A 43.134.249.22
ns3.qq.com. 5 A 43.159.167.11
ns3.qq.com. 5 A 120.204.7.98
ns3.qq.com. 5 A 120.233.255.187
ns4.qq.com. 5 A 43.130.172.24
ns4.qq.com. 5 A 43.161.3.25
ns4.qq.com. 5 A 116.169.38.235
ns4.qq.com. 5 A 125.39.202.11
ns4.qq.com. 5 A 183.60.116.5
ns1.qq.com. 5 AAAA 2402:4e00:c050:7a00:0:0:0:3
ns2.qq.com. 5 AAAA 240e:974:e600:3ee:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0