 A {"mask"} question : {"placeholder": "text_a"} {"placeholder": "text_b"}
 {"placeholder": "text_a"} {"placeholder": "text_b"} This topic is about {"mask"} .
 [ Category : {"mask"} ] {"placeholder": "text_a"} {"placeholder": "text_b"}
 [ Topic : {"mask"} ] {"placeholder": "text_a"} {"placeholder": "text_b"}