我已经开发了我的折线图，但是无法显示一年中的每月（3个月）数据，我明智地显示了这一年，但我无法显示哪一年的交易未显示，给定的json对象
var data=[{"key":[2000,0],"value":100},{"key":[2000,1],"value":200},
{"key":[2001,3],"value":400},{"key":[2001,4],"value":500},
{"key":[2002,1],"value":600},{"key":[2002,1],"value":700},
{"key":[2003,2],"value":500},{"key":[2003,1],"value":800},
{"key":[2004,5],"value":200},{"key":[2004,1],"value":900},
]
var s1=data.map(function (d,i){return {key:d.key[1],value:d.value}})
var x = d3.scale.linear().range([0, width]);
var y = d3.scale.linear().range([height, 0]);
var xAxis = d3.svg.axis().scale(x).orient("bottom").ticks(20)
.tickFormat(d3.time.months,4)
var yAxis = d3.svg.axis().scale(y).orient("left")
var line = d3.svg.line()
.x(function(d) { return x(d.key); })
.y(function(d) { return y(d.value); })
.interpolate("linear")
var svg = d3.select("body").select("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")")
x.domain(d3.extent(s1, function(d) { return d.key; }));
y.domain(d3.extent(s1, function(d) { return d.value; }));
svg.append("path").attr("class", "line").attr("d", line(s1));