如何在R中的林图包中添加垂直参考线（以显示无效果）？我看了一下，似乎必须用gpar和lwd.zero做些事情。作为R的初学者，我不知道如何解决这个问题！
数据
structure(list(X__1 = c("Cognitive test measures", "Duration to entering value
in symbol digit substitution test",
"Fluid intelligence score", "Interval between previous point and current one
in alphanumeric path test",
"Number of correct matches in pairs matching test at assessment centre",
"Number of correct matches in pairs matching test at online follow-up",
"Number of symbol digit matches attempted", "Number of symbol digit matches
made correctly",
"Time to complete round in pairs matching test", "Willing to attempt cognitive
tests",
"Brain-related measures", "Volume of caudate (left)"), coef.1 = c(-0.2,
0.0123382653500193, 0.010814706993287, 0.0142848736074293,
-0.00108701018181296,
0.0026124715662383, -0.0128619156295441, -0.0133119516466763,
0.015106482926049, -0.000828854349199544, -0.2, -0.00278825569529959
), coef.2 = c(-0.2, 0.0261180629713106, -0.0257732078291571,
0.0215601437119394, -0.0488638940065608, -0.00844930188130684,
-0.00986458016040772, -0.00915734591114574, 0.011005161558929,
0.0622608142362833, -0.2, -0.0194947356287098), coef.3 = c(-0.2,
0.0401645543633051, -0.0456862692794778, 0.0315453246538384,
-0.0723340706054082, -0.0865738572277098, -0.0365283919947763,
-0.0378696328351386, 0.0140274847796567, 0.080588996978667, -0.2,
-0.0743007806841494), lower.1 = c(-0.2, 0.000972614864407613,
-0.00778944954946739, 0.00245552059336553, -0.0543803047565877,
-0.0272887125599502, -0.0242289835454776, -0.0247094685100803,
0.00370693545874832, -0.076866214193048, -0.2, -0.0324411007601927
), lower.2 = c(-0.2, 0.015106656922587, -0.0450834257473941,
0.0101646525177104, -0.0875347179037931, -0.0402607369890945,
-0.053029154624216, -0.0525213434515686, 0.00512428484102225,
0.00538318363517092, -0.2, -0.0488217766084101), lower.3 = c(-0.2,
0.0275829521052594, -0.0679922794999653, 0.0182413645530613,
-0.101221399199782, -0.124622632090091, -0.0491750321967264,
-0.0505430256018185, 0.00813947609587589, 0.0391004893167443,
-0.2, -0.115115397354245), upper.1 = c(-0.2, 0.023703915835631,
0.0294188635360414, 0.0261142266214932, 0.0522062843929617, 0.0325136556924269,
-0.00149484771361069, -0.00191443478327225, 0.0265060303933496,
0.073855748425759, -0.2, 0.0268645893695935), upper.2 = c(NA,
0.0371294690200342, -0.00646298991092, 0.0329556349061685, -0.0101930701093285,
0.0233621332264808, 0.0332999943034006, 0.0342066516292771, 0.0168860382768357,
0.118388558209848, NA, 0.00983230535099052), upper.3 = c(NA,
0.0527461566213508, -0.0233802590589904, 0.0448492847546156,
-0.0434467420110343, -0.0485250823653288, -0.0238817517928261,
-0.0251962400684586, 0.0199154934634376, 0.121693431242002, NA,
-0.0334861640140542)), .Names = c("X__1", "coef.1", "coef.2",
"coef.3", "lower.1", "lower.2", "lower.3", "upper.1", "upper.2",
"upper.3"), row.names = c(NA, -12L), class = c("tbl_df", "tbl",
"data.frame"))