その姉妹はたいへん似ている。

that (something or someone distant from the speaker, close to the listener; actions of the listener, or ideas expressed or understood by the listener); the; um...; er...; uh...

sisters

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

very; greatly; immense; enormous; great; serious; grave; dreadful; terrible; difficult; hard; major incident; disaster

to resemble; to look like; to take after; to be similar (in status, condition, etc.); to be close; to be alike; to be like