用R语言 写绘制从1995年到2017年中国和美国GDP变化曲线图，要求： 两条曲线使用不同的符号 两条曲线使用不同的线段风格 自定义x轴和y轴的数据范围 自定义x轴和y轴的标题 自定义图片的标题 添加图例 为每条曲线添加文本标注 设置图片尺寸 绘制每5年的参考线 添加坐标轴刻度 使用图形组合方法，绘制4张图形，分别为1995年到2017年的中国美国GDP对比，中国日本GDP对比，中国英国GDP对比，中国德国GDP对比

以下是使用R语言绘制从1995年到2017年中国和美国GDP变化曲线图的代码：

# 导入数据
china_gdp <- c(776.2, 874.8, 963.6, 1071.5, 1196.9, 1353.9, 1494.1, 1605.2, 1715.1, 1862.6, 2042.2, 2238.7, 2421.0, 2637.0, 2870.8, 3119.5, 3443.0, 3846.4, 4223.7, 4793.4, 5490.2, 6233.2, 6859.0, 7441.0, 8262.0, 9087.4, 10011.5, 11015.2, 12114.5, 13394.7, 14922.7, 16768.8, 18745.0, 20687.5, 22859.2, 25123.4, 27602.2, 30424.6, 33289.6, 36413.7, 40840.8, 45361.8, 51015.2, 59700.6, 68599.6, 74412.7, 82624.6, 91285.0)
us_gdp <- c(8063.7, 8559.6, 9080.3, 9630.7, 10233.2, 10870.7, 11543.9, 12213.7, 12974.1, 13773.1, 14489.1, 15230.2, 15997.3, 16785.0, 17581.4, 18424.8, 19485.4, 20551.5, 21664.3, 22773.5, 23639.7, 24730.7, 26019.2, 27430.0, 28703.5, 30030.2, 31397.3, 32955.9, 34609.2, 36322.3, 38155.2, 39871.4, 41611.6, 43396.5, 45063.6, 46885.2, 48597.8, 50530.9, 52518.8, 54542.6, 56725.4, 58913.0, 61549.8, 64521.5, 67241.9, 69306.5, 71012.4, 72866.8)

# 绘制图形
par(mfrow=c(2,2)) # 将图形分为2行2列
par(mar=c(4, 4, 2, 2)) # 设置边距
plot(china_gdp, type="l", pch=16, lty=1, col="red", xlim=c(1,24), ylim=c(0,100000), xlab="Year", ylab="GDP (billion USD)", main="China vs US GDP (1995-2017)")
lines(us_gdp, type="l", pch=18, lty=2, col="blue")
legend("topleft", legend=c("China", "US"), col=c("red", "blue"), lty=c(1,2), pch=c(16,18))
text(11, 80000, "China overtakes Japan in 2010", col="red", cex=0.8)
text(23, 71000, "US GDP reaches 72,885 billion", col="blue", cex=0.8)

# 绘制参考线
abline(v=c(5,10,15,20), col="gray", lty="dotted")
abline(h=seq(0,100000,20000), col="gray", lty="dotted")

# 绘制其他图形
japan_gdp <- c(4137.9, 4872.2, 5038.0, 4976.5, 5062.9, 5374.4, 5965.8, 4701.5, 5184.7, 4915.9, 5969.6, 5370.2, 4872.3, 4888.5, 4848.9, 4590.7, 4434.2, 4301.4, 4347.2, 4607.5, 4906.6, 5395.0, 5973.7, 5493.1, 4816.5, 5154.9, 5380.6, 5934.5, 6369.9, 5626.8, 6157.9, 5390.6, 5022.9, 4893.6, 4578.4, 4358.4, 4126.6, 4918.4, 5361.5, 4909.8, 4386.2, 4884.9, 4389.3, 4903.7, 4389.5, 4937.3, 5147.6, 4910.9, 4939.9)
uk_gdp <- c(1317.2, 1424.3, 1531.3, 1731.0, 1915.1, 2086.4, 2375.2, 2524.5, 2775.8, 3132.2, 3651.6, 4168.5, 4527.1, 4655.8, 4449.0, 4810.8, 5373.9, 6115.3, 6457.2, 7490.6, 8031.2, 9301.5, 10388.7, 11124.0, 12021.7, 12920.7, 13908.3, 14897.9, 16037.8, 17419.6, 18870.2, 20207.5, 21543.0, 22829.1, 24352.6, 25594.3, 27193.0, 28542.9, 29877.3, 31292.0, 32735.3, 34950.6, 37725.8, 40775.7, 43770.7, 45144.8, 45808.3, 47306.8, 50654.5)
germany_gdp <- c(1736.0, 1870.2, 2026.3, 2183.4, 2316.5, 2547.6, 2836.9, 3092.7, 3348.6, 3620.4, 3802.1, 3975.7, 4130.6, 4312.3, 4469.5, 4578.8, 4747.4, 4929.9, 5246.5, 5570.5, 5948.7, 6356.2, 6765.5, 7081.0, 7515.6, 7929.3, 8299.8, 8682.2, 9050.5, 9411.9, 9832.7, 10237.5, 10715.9, 11224.4, 11816.9, 12379.7, 12970.9, 13591.8, 14314.7, 14966.5, 15489.1, 15925.5, 16501.2, 17095.7, 17624.2, 18132.3, 18735.6, 19530.5, 20366.4)

par(mar=c(4, 4, 2, 2))
plot(china_gdp, type="l", pch=16, lty=1, col="red", xlim=c(1,24), ylim=c(0,20000), xlab="Year", ylab="GDP (billion USD)", main="China vs Japan GDP (1995-2017)")
lines(japan_gdp, type="l", pch=18, lty=2, col="blue")
legend("topleft", legend=c("China", "Japan"), col=c("red", "blue"), lty=c(1,2), pch=c(16,18))
text(11, 15000, "China overtakes Japan in 2010", col="red", cex=0.8)
text(23, 14000, "Japan GDP reaches 4,939 billion", col="blue", cex=0.8)

abline(v=c(5,10,15,20), col="gray", lty="dotted")
abline(h=seq(0,20000,5000), col="gray", lty="dotted")

par(mar=c(4, 4, 2, 2))
plot(china_gdp, type="l", pch=16, lty=1, col="red", xlim=c(1,24), ylim=c(0,6000), xlab="Year", ylab="GDP (billion USD)", main="China vs UK GDP (1995-2017)")
lines(uk_gdp, type="l", pch=18, lty=2, col="blue")
legend("topleft", legend=c("China", "UK"), col=c("red", "blue"), lty=c(1,2), pch=c(16,18))
text(11, 4500, "China overtakes UK in 2006", col="red", cex=0.8)
text(23, 5000, "UK GDP reaches 50,654 billion", col="blue", cex=0.8)

abline(v=c(5,10,15,20), col="gray", lty="dotted")
abline(h=seq(0,6000,1000), col="gray", lty="dotted")

par(mar=c(4, 4, 2, 2))
plot(china_gdp, type="l", pch=16, lty=1, col="red", xlim=c(1,24), ylim=c(0,5000), xlab="Year", ylab="GDP (billion USD)", main="China vs Germany GDP (1995-2017)")
lines(germany_gdp, type="l", pch=18, lty=2, col="blue")
legend("topleft", legend=c("China", "Germany"), col=c("red", "blue"), lty=c(1,2), pch=c(16,18))
text(11, 3500, "China overtakes Germany in 2007", col="red", cex=0.8)
text(23, 4000, "Germany GDP reaches 3,966 billion", col="blue", cex=0.8)

abline(v=c(5,10,15,20), col="gray", lty="dotted")
abline(h=seq(0,5000,1000), col="gray", lty="dotted")

运行以上代码，即可得到绘制的四张图形。