tokens: the ICME structure and how the structure controls the geomagnetic activity. These results are summarized and discussed below, which illustrate the importance of multi-spacecraft remote-sensing and in situ observations for understanding the physical processes of CME propagation and space weather forecasting. 1. This study compares STEREO stereoscopic wide-angle imaging observations with multi-point in situ measurements at Mercury and Earth, which places a strong constraint on CME Sun-to-Earth propagation. The CME kinematics determined from the triangulation technique predicts well the shock arrival time at MESSENGER with an error of about 1 hr in this study. A reasonable accuracy is also obtained when we compare the predicted arrival time and speed with the in situ measurements near the Earth. From the Sun to Earth, the CME undergoes an impulsive acceleration, a rapid deceleration, and then a gradual deceleration out to 1 au, which agrees with the conclusions of Liu et al. ( 2013 , 2016 ). We find that the rapid deceleration ceases at ∼50 before the CME reached MESSENGER (∼0.47 au), which is different from the coronagraph findings in Gopalswamy et al. ( 2001a ). Combining this case with the three events in Liu et al. ( 2013 ), we suggest that fast CMEs are likely to terminate deceleration before reaching 100 from the Sun, which should be noticed in kinematics models of fast CMEs. This work once again proves the reliability of the stereoscopic triangulation technique in determining the kinematics of earthward CMEs in the inner heliosphere. 2. Our comparison between wide-angle imaging observations and the interplanetary type II radio burst indicates important clues on the source region of the type II burst. The study reveals that the consistency between the shock distance derived from the type II radio burst and the CME kinematics determined by the triangulation method requires an unusually high solar wind electron density. The type II radio burst was probably produced from a high-density region. This discrepancy and the slow increasing distance of the CME-driven shock derived from the type II radio burst can be explained by the shock interacting with nearby streamers (e.g., Reiner et al. 2003 ; Cho et al. 2007 ; Feng et al. 2012 ). Another possibility is that the type II radio burst was generated by the shock flank region with lower heights (Claßen Aurass 2002 ; Knock et al. 2003 ). Because only one spacecraft detected the type II radio burst, it is not possible to determine the position of the source region using the radio triangulation method of Martínez-Oliveros et al. ( 2015 ). This result implies uncertainties in the determination of CME kinematics using type II radio bursts alone. 3. We reconstruct the ICME structure near the Earth in order to connect it with the solar source observations and to understand how the structure contributes to the geomagnetic storm. The flux-rope inclination angle and chirality at 1 au are consistent with those
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