the puzzle about the difference between the CCM and DCM in the TI's technologic article "inductor and flyback transform designer"

The article express the CCM and DCM is:

.Discontinuous inductor current mode. when the

instantaneous ampere-turns (totaled in all windings)

dwell at zero for a portion of each switching

period.

.Continuous inductor current mode. in which the

total ampere-turns do not dwell at zero (although

the current may pass through zero).

Question:  the differences between the "the ampere-turns is do not dwell at zero" and "the inductor current do not dwell at zero".What is the substantial between the Dcm and Ccm.

wait for your answer.

ampere-turns：安匝数 inductor current 电感电流，本质应该是一样的吧，本质区别就是在每个开关周期，DCM电感电流要降低到零，CCM电感电流不降低到零。

The reply is not the answer I wished.  Thk!