They usually have the medicine ______ be
问题:
They usually have the medicine ______ before putting into the market all over the country. [ ]
A. testing out
B. to be tested out
C. being tested out
D. tested out
They usually have the medicine ______ before putting into the market all over the country. [ ]
A. testing out
B. to be tested out
C. being tested out
D. tested out