日韩欧美亚洲 _ 欧美亚洲一区 _ 日本亚洲欧美 _ 亚洲精品欧美国产白袜脚足J棉袜在线观看_亚洲熟妇av一区二区三区_久久天天躁狠狠躁夜_精品众筹模特私拍在线

填空題

It may be necessary to stop（）(每隔一定時間) in the learning process and go back to the difficult points in the lessons.

答案： at intervals

你可能感興趣的試題

There’s a man at the reception desk who seems very angry and I think he means（）(想找麻煩).

答案： to make trouble

We’d like （）(預(yù)訂一張餐桌) five for dinner this evening.

答案： to reserve a table for