Recognize more openers of secondary clauses in mainClause

src/3-three/sentences/parse/mainClause.js

@@ -1,5 +1,6 @@
 // if a clause starts with these, it's not a main clause
-const subordinate = `(after|although|as|because|before|if|since|than|that|though|when|whenever|where|whereas|wherever|whether|while|why|unless|until|once)`
+// followed by a number, 'since' or 'once' is a preposition or an adverb ('since 2010', 'once upon a time')
+const subordinate = `(after|although|as|because|before|if|since|than|that|though|when|whenever|where|whereas|wherever|whether|while|why|unless|until|once) !(#Value|upon|then|now)`
 const relative = `(that|which|whichever|who|whoever|whom|whose|whomever)`
 
 // a subordinator or relative pronoun only makes the clause secondary when it
@@ -34,6 +35,7 @@ const mainClause = function (s) {
   m = m.ifNo('^so that')
   m = m.ifNo('^rather than')
   m = m.ifNo('^provided that')
+  m = m.ifNo('^in case')
   if (m.length === 1) {
     return m
   }
@@ -55,6 +57,13 @@ const mainClause = function (s) {
     return m
   }
 
+  // an infinitive or an inverted condition ('To win ...', 'Had I known ...')
+  m = m.ifNo('^to #Infinitive')
+  m = m.ifNo('^#Condition')
+  if (m.length === 1) {
+    return m
+  }
+
   // did we go too far?
   if (m.length === 0) {
     m = s

tests/three/sentences/svo.test.js

@@ -47,6 +47,9 @@ test('svo parser', function (t) {
     ],
     ['He bought the car that the dealer, the bank, and the broker all recommended.', 'he', 'bought'],
     ['I ate dinner before I went to bed.', 'i', 'ate'],
+    ['To win the race, you must train every day.', 'you', 'must train'],
+    ['Had I known, I would have left earlier.', 'i', 'would have left'],
+    ['In case you forget, we will remind you.', 'we', 'will remind'],
 
     // ['every day the kitten tries to eat the mouse', 'the kitten', 'tries to eat'],
     // ['The boy who you saw at the store committed a robbery.', 'the boy', 'committed'],
@@ -62,3 +65,15 @@ test('svo parser', function (t) {
   })
   t.end()
 })
+
+test('svo main clause after a preposition', function (t) {
+  const arr = [
+    ['Since 2010 we have lived here, and we love it.', 'have lived'],
+    ['Once upon a time there lived a king, and he was rich.', 'lived'],
+  ]
+  arr.forEach(a => {
+    const obj = nlp(a[0]).sentences().json()[0]
+    t.equal(obj.sentence.verb, a[1], here + 'verb: ' + a[1])
+  })
+  t.end()
+})