题干
My mother often cooks _______ for us.
A：something delicious
B：delicious something
C：anything delicious
D：delicious anything
答案(点此获取答案解析）
A
My mother often cooks _______ for us.
A：something delicious
B：delicious something
C：anything delicious
D：delicious anything
的前4项依次是20，11，2，－7的一个通项公式是（ ）