問題詳情

21. The most serious health problem ________ infectious diseases. Today, the number one health problem inthe United States is obesity.
(A) was used to be
(B) used to have been
(C) used to be
(D) was used to being

參考答案

答案：C
難度：簡單0.625
書單：沒有書單，新增

用户評論

【用戶】熊熊讚

【年級】高三下

【評論內容】The most serious health problem used to be infectious diseases. Today, the number one health problem in the United States is obesity.最嚴重的健康問題曾經是傳染病。 如今，美國的頭號健康問題是肥胖。

【用戶】熊熊讚

【年級】高三下

【評論內容】The most serious health problem used to be infectious diseases. Today, the number one health problem in the United States is obesity.最嚴重的健康問題曾經是傳染病。 如今，美國的頭號健康問題是肥胖。

【用戶】熊熊讚

【年級】高三下

【評論內容】The most serious health problem used to be infectious diseases. Today, the number one health problem in the United States is obesity.最嚴重的健康問題曾經是傳染病。 如今，美國的頭號健康問題是肥胖。