How long _____ you last saw her?[ ] A. i

在中国流行最广泛的疟原虫种类是（）.

A.恶性疟原虫

B.间日疟原虫

C.三日疟原虫

D.卵形疟原虫

葡萄酒陈酿对酒窖的要求

某建筑工地用如图所示的简易滑轮组将重4000N的砖块运到离地4m高的砌墙处，已知每个滑轮重100N，滑轮摩擦和绳重以及动滑 轮下的挂网重忽略不计．若提升砖块的工人作用于绳的拉力最大为500N，求：

（1）提升一次砖的最大重力；

（2）提升一次砖时滑轮组的最大机械效率；

（3）若全部完成提砖任务，工人利用此滑轮组至少做多少额外功．

Today, the Indianapolis 500, one of the world’s most famous car races, takes about four hours to run. If the Indy 500 had been held in 1895, it would have taken almost three days. The horseless carriage had just been invented a short time before. Top speeds back then were much lower than they are today. For most people, just seeing a car move without a horse pulling it was thrilling enough. The driver’s main concern was making sure the car didn’t break down.
One of the first car races was held in Chicago on Thanksgiving Day in 1895. Folks crowded the streets to gawk at the new machines. The route of the race went through the heart of town. The cars were to go out to a nearby suburb and back. The race covered a distance of about 54 miles. That’s less than one-tenth the distance at Indy. The drivers cranked up their engines and prayed that they wouldn’t break down. Then they were off. The race proved too much for some of the cars. Perhaps they couldn’t withstand the high speeds. The winner of the contest was J. Frank Duryea. He finished the race a bit more than seven hours after he started. He had covered the grueling distance at an average speed of 7.5 miles per hour. That is slower than a modern marathoner can go on foot. Even so, as Duryea finished, the crowd went wild.

This passage deals with______.

A．the Indianapolis 500

B．a new kind of car

C．an early auto race

D．the streets of Chicago

从三果迈向四果用什么法？