[Q]: Would the following sentence, by the strictest standards, be considered correct? To delay the march and to go ahead with it has been argued by different people at different times.
++++++++++
[A]: unacceptable

[Q]: Would the following sentence, by the strictest standards, be considered correct? Mary won't have been eating cake, but John will have been.
++++++++++
[A]: acceptable

[Q]: Would the following sentence, by the strictest standards, be considered correct? They waltzed.
++++++++++
[A]:
acceptable