问题
选择题
We'll have a picnic in the park this Sunday ________ it rains or it's very cold.[ ]
A. since
B. if
C. unless
D. until
答案
答案:C
We'll have a picnic in the park this Sunday ________ it rains or it's very cold.[ ]
A. since
B. if
C. unless
D. until
答案:C