A:looked into
B:looked u
C:looked through
D:looked after
将5本不同的书摆成一排,若书甲与书乙必须相邻,而书丙与书丁不能相邻,则不同的摆法和数为____
—What's the meaning of"One Belt and One Road"?
—Let me ________ the words in the new dictionary.