The most reliable symptom of an underactive thyroid gland is a relentless coldness in the centre of the body. What's interesting is that cold hands and feet, especially indoors or in a warm environment, are not a reliable sign of hypothyroidism.
sit on someone or something. 1. Lit. to place oneself in a sitting position on someone or something. The enormous woman knocked the crook out and sat on him until the police came. I need to sit on this chair for a minute and catch my breath. 2. Fig. to hold someone or something back; to delay someone or something. The project cannot be finished because the city council is sitting on the final approval. Ann deserves to be promoted, but the manager is sitting on her because of a disagreement.
onto / off. Onto and off refer to surfaces, differently from into / out of (which refer to enclosed spaces): 1  The dog jumped onto the table. The dog jumped into the table.  I took the picture off the wall. I took the picture out of the wall.