I have a content type that has 3 term reference fields: A, B, and C.

User fill in A and B, by rules get A and B then action set data value to C, but it only sets one value. What can I do to set multiple values?

{ "rules_juhe_xieru" : {
    "LABEL" : "\u805a\u5408\u5206\u7c7b\u81ea\u52a8\u5199\u5165",
    "PLUGIN" : "reaction rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "rules" ],
    "ON" : { "node_insert--mfpf" : { "bundle" : "mfpf" } },
    "DO" : [
      { "data_set" : { "data" : [ "node:field-juhe-fenlei" ], "value" : [ "node:field-diqu" ] } }
    ]
  }
}

I have a content type that has 3 term reference fields:

• Field A (required), which contains a single tag.
• Field B (required), which contains a single tag.
• Field C (not required), which contains a single tag.

The tags from those 3 fields all related to the same taxonomy.

When creating or updating a node, values are entered for field A and B. I want to have a rule ((using the Rules module) with some Rules Action to set a data value for field C, equal to the concatenation of the value entered for field A and B. But "set a data value" only sets one value. 

What can I do to set multiple values?

Some more screenprints to explain all this:

And here is my current Rule I'm trying to get to work:

{ "rules_juhe_xieru" : {
    "LABEL" : "\u805a\u5408\u5206\u7c7b\u81ea\u52a8\u5199\u5165",
    "PLUGIN" : "reaction rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "rules" ],
    "ON" : { "node_insert--mfpf" : { "bundle" : "mfpf" } },
    "DO" : [
      { "data_set" : { "data" : [ "node:field-juhe-fenlei" ], "value" : [ "node:field-diqu" ] } }
    ]
  }
}

I have a content type that has 3 term reference fields: A, B, and C.

User fill in A and B, by rules get A and B then action set data value to C, but it only sets one value. What can I do to set multiple values?

{ "rules_juhe_xieru" : {
    "LABEL" : "\u805a\u5408\u5206\u7c7b\u81ea\u52a8\u5199\u5165",
    "PLUGIN" : "reaction rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "rules" ],
    "ON" : { "node_insert--mfpf" : { "bundle" : "mfpf" } },
    "DO" : [
      { "data_set" : { "data" : [ "node:field-juhe-fenlei" ], "value" : [ "node:field-diqu" ] } }
    ]
  }
}

I have a content type that has 3 term reference fields: A, B, and C.

User fill in A and B, by rules get A and B then action set data value to C, but it only sets one value. What can I do to set multiple values?

{ "rules_juhe_xieru" : {
    "LABEL" : "\u805a\u5408\u5206\u7c7b\u81ea\u52a8\u5199\u5165",
    "PLUGIN" : "reaction rule",
    "OWNER" : "rules",
    "REQUIRES" : [ "rules" ],
    "ON" : { "node_insert--mfpf" : { "bundle" : "mfpf" } },
    "DO" : [
      { "data_set" : { "data" : [ "node:field-juhe-fenlei" ], "value" : [ "node:field-diqu" ] } }
    ]
  }
}