A、with
B、to
C、at
D、by
第1题:
A.Has-arelationshipsshouldneverbeencapsulated.
B.Has-arelationshipsshouldbeimplementedusinginheritance.
C.Has-arelationshipscanbeimplementedusinginstancevariables.
D.Is-arelationshipscanbeimplementedusingtheextendskeyword.
E.Is-arelationshipscanbeimplementedusingtheimplementskeyword.
F.Anarrayoracollectioncanbeusedtoimplementaone-to-manyhas-arelationship.
G.TherelationshipbetweenMovieandActressisanexampleofanis-arelationship.
第2题:
The population of the world ____ still ____ now.
A.has; grown B.is; growing C.will; grow D.is; grown
第3题:
将students中的列变量重新命名为: (1)id_number, name, gender, score, has_graduate (2)选出Bob的性别gender,并存入变量bob_gender (3)选出列has_graduate,并存入向量status (4)创建数据框part_df,其中包含前三个学生的所有信息 (5)创建数据框rest_df,包含其余学生的所有信息
第4题:
When William hurried home, he found that his mother ____already ____to hospital.
A、has; been sent
B、had; sent
C、has; sent
D、had; been sent
第5题: