The young man stepped into the office ,___down and began to fill in the forms.
问题描述：
The young man stepped into the office ,___down and began to fill in the forms.
答
sat 因为是过去得一连串的动作。句式是这样的：did ,did and did .先进办公室，然后坐下，然后填表格。
答
( sat ) down----------------坐下来
答
过去式用sat