He ---- ----- ----- ----- ------(有.的习惯）going shopping on sat

is in the habit of
in the habit of 是一个固定搭配的短语,表示"有...的习惯"
如:I am in the habit of rising with the sun.
我有太阳出来就起床的习惯.
Nowadays,a lot of people are in the habit of cutting calories before eating.
现在有很多人都有在用餐前消耗卡路里(热量)的习惯.