When you go on a thing like this, we can usually be in the field for anywhere from two to four months, with a team as small as 20 or 30, to as big as 150.
当我们到了这样的岩洞时，我们经常会在那 待二至四个月， 我们的队伍规模小时二三十人，大时有一百五十人。