问题补充：
This is the first thing you are after you get there.
A. suppose to do
B. supposed do
C. supposed to do
D. supposed doing
答案：
A. suppose to do
B. supposed do
(答案→)C. supposed to do
D. supposed doing
解析：句意：这是你到达那里后首先要做的事。be supposed to do sth是固定搭配，表示“应该要做某事” ，故应选C。
