Add spaces: 14Iamnotabletobearallthispeoplealone,becauseitistooheavyforme.

Answer: 14 I am not able to bear all this people alone, because it is too heavy for me.

Add spaces: Oneofacentrespeaker’smostimportantjobsistoreproducefilmdialogue.

Answer: One of a centre speaker’s most important jobs is to reproduce film dialogue.

Add spaces: Ishallalsoshowaphysical-mechanicalconnectionbetweenwhatwecallrespectively'gravitational'forcesand'electrical'forces.

Answer:
I shall also show a physical-mechanical connection between what we call respectively 'gravitational' forces and 'electrical' forces.