You can only be sure of you have at present;you cannot be sure of something you might get in the future.
A. that;what
B. what;/
C. which;that
D. /;that
网友回答
A. that;what
(答案→)B. what;/
C. which;that
D. /;that
解析：what引导宾语从句，作介词of的宾语，what在宾语从句中作have的宾语。something后接定语从句，可以省略that。