This is 3-D printer. And this is an artificial (人工的) ear. Can you believe that scientists printed this artificial ear by this 3-D printer?
#33175
A
a
B
an
C
the
D
/
推荐题目
There is ___________ “s” and __________ “u” in _______word “student”.
#33869
A
a, a, an
B
an, an, the
C
a, an, a
D
an, a, the
