单选题

There are four questions below，

Along a street that is currently without trees, seven trees are to be planted in the pattern

单选题

Which of the following can be the trees planted along the side of the street that has four trees, in order of their positions beginning with position 1？

A、 Maple, sycamore, maple, sycamore
B、 (BMaple, sycamore, red oak, maple
C、 Red oak, maple, maple, red oak
D、 Sycamore, sycamore, maple, maple
E、 Sycamore, sycamore, red oak, red oak

【正确答案】 E

【答案解析】

单选题

If red oaks are used, then which of the following must be true？

A、 The other trees used are all maples
B、 The other trees used are all sycamores
C、 The red oaks are in positions 1, 2, and 3.
D、 The red oaks are in positions 3, 4, and 5.
E、 The red oaks are in positions 4, 5, and 6.

【正确答案】 B

【答案解析】

单选题

Among the trees left over after the planting is done there must be

A、 at least one maple
B、 at least one red oak
C、 at least one sycamore
D、 at most one maple
E、 at most one red oak

【正确答案】 A

【答案解析】

单选题

If maples are planted, the side of the street that has four trees must have

A、 red oaks in positions 1 and 7
B、 red oaks in positions 3 and 5
C、 sycamores in positions 1 and 3
D、 sycamores in positions 1 and 7
E、 sycamores in positions 3 and 5

【正确答案】 E

【答案解析】