【多选题】
利用循环求1到5的和值，已知i=1，sum=0；利用循环每次让sum求和，然后i++；判断条件是i<6；则求和的循环操作是（）。
①
sum=sum+i
②
sum+=i
③
sum=i
④
i=sum+i
【单选题】
以下程序段运行后sum的值为（）。intk=0,sum=0;inta[3][4]={1,2,3,4,5,6,7,8,9,10,11,12};for(;kk++)sum+=a[k][k+1];
①
9
②
18
③
19
④
21
【单选题】
It was not until he arrived in class _____ realized he had forgotten his book.
①
when he
②
that he
③
and he
④
he
【单选题】
Its free, so you neednt ____________ money ____________ me.
①
give...to
②
pay...for
③
borrow...from
④
cost...for
【单选题】
Its free, so you neednt ____________ money ____________ me.
①
take...from
②
pay...for
③
borrow...from
④
cost...for
【单选题】
The old man got into the ___ of storing money under the bed.
①
tradition
②
habit
③
use
④
custom