In order to obtain new Actions object call WebDriver.Actions.

var actions = WebDriver.Actions();

Then construct your action, build and perform it.

var el1 = WebDriver.FindElementByXPath("//select[@id='ctrl07']/option[1]");
var el2 = WebDriver.FindElementByXPath("//select[@id='ctrl07']/option[2]");
var el3 = WebDriver.FindElementByXPath("//select[@id='ctrl07']/option[3]");

actions.KeyDown("Shift").Click(el1).Click(el2).Click(el3).KeyUp("Shift").Perform();

Here is one liner example.

WebDriver.Actions().KeyDown("Shift").Click(el1).Click(el2).Click(el3).KeyUp("Shift").Perform();

Actions class is described in Rapise help file.

Check out the sample test on GitHub.