On many trains and buses, there are some special seats ________ out for senior citizens. 
#92562
A
marking
B
marked
C
to mark
D
mark
推荐题目
What’s the chance of ________ a general election this year?
#90576
A
there being
B
there to be
C
there be
D
there going to be
English is a language ______ in many countries.
#97552
A
spoken
B
speaking
C
be spoken
D
to speak