切开苹果、梨等水果时会流出一些汁液，这些汁液主要来自（ ） A．细胞质 B．细胞

肉桂醛是一种食用香精，它广泛用于牙膏、洗涤剂、糖果以及调味品中。工业上可通过下列反应制备

(1)请推测B侧链上可能发生反应的类型：_________________________。(任填两种)

(2)请写出两分子乙醛在上述条件下反应的化学方程式：_____________________________。

(3)请写出同时满足括号内条件下B的所有同分异构体的结构简式：(①分子中不含羰基和羟基；②是苯的对二取代物；③除苯环外，不含其他环状结构。）______________________。

. It’s a good rule to _____.

A．according to

B．lead to

C．go along

D．go by

桩距大于（）倍桩径时，打桩顺序对土体挤压影响不大。

“标格亦资于诂训”中“标格”的意思是（）

A.完善的理论

B.完备而周密的见解

C.经文的精髓要旨

D.对经文正确理解的标准

E.全面陈述阐发

(41)Orientation
Yellowstone is much more than hot ground and gushing steam. Located astride the Continental Divide, most of the park occupies a high plateau surrounded by mountains and drained by several rivers. Park boundaries enclose craggy peaks, alpine lakes, deep canyons, and vast forests. In 1872, Yellowstone became the world’s first national park, the result of great foresight on the part of many people about our eventual need for the solace and beauty of wild places.
(42) When to Go
More than half of the 3 million annum visitors come in July and August. In September and early October, the weather is good, the visitors few, and the wildlife abundant. In May and June, you can see newborn animals, but the weather may be cold, wet, and even snowy. Between about No-vember 1 and May 1 most park roads are closed to vehicles.
(43) Getting There
(44) How to Visit
The 142-mile (228.5-kilometer) Grand Loop Road forms a figure eight, with connecting spurs to the five entrances. On any visit, start with the geyser basins and Mammoth Hot Springs to see wildlife and thermal features (caution: both can be hazardous if approached too closely). On the second day, travel to the Grand Canyon of the Yellowstone, Hayden Valley, and Yellowstone Lake.
(45) Park Information
Park opens year-round.
[A] Road from North Entrance to Northeast Entrance open all year; most other park roads closed to cars November through April. Call headquarters for latest weather and road conditions.
[B] Facilities for Disabled Visitor centers, Madison and Fishing Bridge Campgrounds, most rest rooms, amphitheaters, numerous ranger-led activities, walks, and exhibits are wheelchair accessible. Free brochure available.
[C] On a longer stay, visit the Northern Range, or consider a boating or fishing trip on Yellowstone Lake; a backcountry excursion on foot or horse; or any of the numerous easy nature trails throughout the park.
[D] In early years, what made Yellowstone stand out was the extravaganza of geysers and hot springs. The wild landscape and the bison, elk, and bears were nice but, after all, America was still a pioneer country filled with scenic beauty and animals.
[E] By Plane
West Yellowstone Airport (WYS) at the West Entrance of Yellowstone. (This airport is open June through September.)
Cody Airport (COD) about 50 miles (81 kilometers) from the park.
[F] During the winter season, mid-December to mid-March, Yellowstone becomes a fantasy of steam and ice; facilities are limited but sufficient. Only the road between the North and Northeast Entrances stays open to cars, but snowmobiling is permitted on unplowed roads. Heated snow coaches offer tours and give cross-country skiers access to the 50 miles (80.5 kilometers ) of groomed trails.