A：whenever
B：no matter
C：wherever
D：however
在胎儿生长发育的过程中，母亲与胎儿之间进行物质交换的场所是（ ）
若x1，x2是一元二次方程x2-8x+15=0的两个根，则x1+x2的值是（ ）
根据材料，选择正确答案。
In Sunshine Town if you want to go to the cinema or theatre, look at the following first.
Sunshine Theatre (PLAYS ONLY)
Open: 11:30 a.m.-7:30 p.m. from Monday to Sunday
Ticket price: Member price:￥30 Usual price:￥40 Student:￥15
Telephone: 010-6697 3219
Sunshine Cinema
Open: 9:00 a.m.-8:00 p.m. Monday to Sunday
Ticket price:￥40 (half price on Tuesday)
Telephone: 010-6699 9977; 010-6699 6644
Sunshine Modern Cinema
Open: 10:30 a.m.-11:30 p.m. from Monday to Friday
10:00 a.m.-11:30 p.m. Saturday and Sunday
Ticket price: Adults:￥50 Children (under 14):￥10
The old (over 60):￥20 The young (15-18):￥20
Telephone: 010-6699 3834
