单选题 To develop their artistic creativity, children should been encouraged to ___.

单选题 Parents are encouraged to be role models for their kids because___.

单选题 Water encourages the ____ of iron and oxygen to form rust.

单选题 The advantage of chevrons over straight, horizontal bars is that the former ___.

单选题 The passage mainly discusses ___.

单选题 You can’t get across the river ____ by swimming.

单选题 On roads painted with chevrons, drivers tend to feel that ___.

单选题 老年人乐意呈现出他们的年龄