4.— Did you have anyone ______the trees?
—Yes,l had the trees ______.
A. to water ;water
B. to water; watered
C. water ; to be watered
D. water; watered
第1题:
______the survivors know more of how to cope with cold water in the sinking of MV Titanic in 1912 countless lives ______.
A.Have / could have been saved
B.Have / could have saved
C.Had / could has saved
D.had / could have been saved
第2题:
You look() What()you()?
Atire;did;do
Btiring;have;done
Ctired;do;do
Dtired;have;been doing
第3题:
要查看stats包中的数据集trees的某一列数据,比如仅查看Girth列的命令是
A.trees$Girth
B.trees[Girth]
C.trees(Girth)
D.trees.Girth
第4题:
第5题:
要查看stats包中的数据集trees的前10行数据的命令是
A.trees(1:10)
B.trees(1:10,)
C.trees[1:10]
D.trees[1:10,]