问题：
The language system must constantly _______a new environment and situation to survive and flourish.
[ ]
A. refer to
B. adjust to
C. see to
D. tend to
The language system must constantly _______a new environment and situation to survive and flourish.
B. adjust to
C. see to
D. tend to
[ ]
A. refer to B. adjust to
C. see to
D. tend to
参考答案：